Things were just too quiet in the NFL. The Bills and Eagles sent shock waves around the league Tuesday evening with reports of a stunning trade that defies simple analysis. Buffalo’s acquisition of running back LeSean McCoy in exchange for linebacker Kiko Alonso is a football rarity, a meaningful player-for-player swap where both teams can make a case they bought low and sold high. Both sides are assuming large amounts of risk, albeit in vastly different ways. The NFL doesn’t see very many trades like these. This is a fascinating exception, and a heck of a way to spend 20 minutes.

This trade really ran the gamut of reactions. I heard from everybody — from people within the league to friends who are fans of the teams involved — and the range of responses was extraordinary. Some saw this as a franchise-destroying mark of ultimate hubris for the Eagles. Others saw it as a sign that the Bills are just going to make the same futile mistakes they’ve made during their 15-season vacation from postseason play. I think it’s unfair to jump to those conclusions; this isn’t a deal with an obvious winner at the moment, even if it is the sort of trade that seems likely to end with one side regretting its decision. It’s a shocking trade — not necessarily a bad one.

Even if this isn’t a swap with a clear winner on its face, it’s a deal that raises all kinds of questions. Let’s answer them and get some insight into the pros and cons for both teams.

Why did the Eagles trade away McCoy?

It all starts here, right? This doesn’t feel like a trade where the Eagles said to themselves, “We have to acquire Kiko Alonso,” and just happened to settle on McCoy as the cost. It feels like a deal where the Philadelphia organization decided it was time to move on from its star running back and found Alonso to be the best option available.

Why would the Eagles want to move on from their franchise running back? Put yourself in their shoes and you can come up with a number of reasons. Start with McCoy’s production, which declined noticeably last year after a career season in 2013. While McCoy stayed healthy for the second consecutive season, his rushing average dropped precipitously, falling from a robust 5.1 yards per carry in 2013 to a far more middling 4.2 yards last year.

While McCoy seemed less explosive last season, that drop-off was more gradual than it might seem. McCoy had nine carries of 20 yards or more on 312 rushing attempts in 2014 … after posting nine carries of 20 yards or more on 314 rushing attempts in 2013. His longest run in 2013 (57 yards) was similar to his longest rush of 2014 (53 yards). His profile as a long-distance runner was not dramatically different between the two seasons under Chip Kelly.

Instead, McCoy’s performance suffered in the context of keeping the Eagles offense on schedule. Football Outsiders has a running back statistic called Success Rate that tracks how effectively backs keep their team on pace for first downs. A successful run, by its standards, is one that picks up 40 percent of the yards needed for a conversion on first down, 60 percent on second down, or 100 percent on third or fourth down. McCoy’s Success Rate in 2013 was 52 percent, the eighth-best rate in the league. Last year, it fell to 45 percent, which was 22nd among 43 qualifying running backs.

Some of that falls on McCoy’s inimitable running style, which relies on his unfathomable agility in the backfield to cut back and make free defenders miss behind the line of scrimmage before bursting upfield. When that works, it looks incredible. When it doesn’t, you start hearing rumblings about how McCoy needs to be more of a north-south runner and hit the hole before the defenders can even make it into the backfield. (Kelly, at least publicly, suggested that he only cared about McCoy’s production.)

The other factor is the one that should leave Bills fans wary. In 2013, the Eagles turned their offense around with a mammoth season from what was widely regarded as the league’s best offensive line. The Philly front five finally stayed healthy for all 16 games and delivered a dominating campaign. Last year, the Eagles were beset by injuries up front, eventually starting 10 linemen during a frustrating campaign. That goes both ways for McCoy; the healthy line surely inflated his numbers in 2013, but it also affected them last season.

Buffalo’s offensive line stayed mostly healthy last season, as the only starter to miss time was guard Chris Williams, an ill-advised free-agent pickup whose season ended after just three games because of a back injury. The problem was, the line just wasn’t very good. The Bills ranked just 26th in Adjusted Line Yards, and while those numbers can be misleading, Buffalo’s reputation matches the metrics here. The Bills added Richie Incognito earlier this offseason, but in addition to whatever odiousness Incognito brings as a human being, he wasn’t very good for the Dolphins on the field in 2013 and was out of football last year. McCoy will need to make his own magic happen again in 2015.

What about the money?

This has to be the biggest reason the Eagles made this trade. McCoy’s deal is onerous. He had a $12 million cap hit coming for Philadelphia in 2015, which would have only been topped among running backs by Adrian Peterson, and Peterson’s deal may also be ripped up and renegotiated very soon. By trading McCoy, the Eagles incur $3.4 million in dead money on this year’s cap but otherwise save $8.6 million in 2015.

Those are the direct savings. Acquiring Alonso as opposed to a draft pick also allows the Eagles to clear out cap space elsewhere. The Eagles will plug in Alonso at inside linebacker in their 3-4 defense, where he’ll play alongside promising young incumbent Mychal Kendricks. Alonso will replace veteran DeMeco Ryans, who tore his Achilles for the second time last season and will now likely be released. While the Eagles might have released Ryans even without acquiring Alonso, the difference between Alonso’s cap hit in 2015 (just under $800,000) and Ryans’s ($6.9 million) will give the Eagles a cool $6.1 million more in cap space to work with this offseason.

It certainly seems like the Eagles are trying to clear out as much cap space as possible with a plan in mind. They have been busy this week outside the McCoy trade, cutting Cary Williams and planning to do the same with Trent Cole. Releasing those veteran defenders will create $14.9 million, and if the Eagles also release Ryans, that adds up to $29.5 million in newly free cap space.

What will the Eagles do with all of that space?

It opens up all kinds of possibilities. This is a scary thing to say after Philadelphia lived through the Dream Team, but the Eagles can sign whomever they want in free agency. Ndamukong Suh? The Eagles can comfortably give him a hefty signing bonus and an enormous guaranteed first-year base salary without having to corrupt their cap in years to come. Byron Maxwell might as well pack his bags now. Devin McCourty is in play. And this makes Jeremy Maclin easier to re-sign if the Eagles are interested. If you can dream it, the Eagles can do it.

The most interesting options, though, are a pair of offensive weapons Kelly might find to his liking. McCoy’s impending departure means the top running back on Philadelphia’s roster will be Chris Polk, with Darren Sproles limited to a situational role. Could the Eagles be interested in going after DeMarco Murray, a move that would weaken their division rivals in Dallas while giving Kelly a more consistent back who was fourth in the league in Success Rate last season? Or could the Eagles go after 24-year-old Packers star Randall Cobb, whose versatility could allow Kelly to line him up anywhere on the field as a mismatch?

There are reasons to argue against both options; Murray is coming off a year of overuse in Dallas, and the 5-foot-10 Cobb is hardly the sort of big, physical receiver Kelly seems to favor when he’s making the personnel calls. But it’s clear that part of this trade revolves around what the Eagles do with the cap space they’ve cleared out. McCoy for Alonso is curious. McCoy for Alonso and Cobb? That’s a lot more appealing if you’re an Eagles fan.

So why would the Bills trade for McCoy if the Eagles are so eager to shed his salary?

Because this is the sort of thing you do when you don’t have a quarterback or any path toward getting one. With their first-round pick shipped to Cleveland in last year’s Sammy Watkins trade, the Bills can’t formulate a credible offer to trade up and grab Marcus Mariota, even if they thought he was worth the risk. Kyle Orton’s retirement has left them with EJ Manuel and Jeff Tuel at quarterback, and given that the Bills paid Orton a comfortable sum to come out of semi-retirement and hop into the lineup last year, you can figure out just how little Manuel showed in camp. I mean, the Bills were just outbid for Josh McCown and actually upset about it. This is the worst quarterback situation in football.

The Bills will surely head into the veteran free-agent market and come away with somebody like Jake Locker or Brian Hoyer on a short-term deal, but there’s no long-term option at quarterback available to them until the 2016 draft. And even with a dominant defense, Manuel (or Locker, or Hoyer) is so subpar that they’ll need an excellent running game to win. Adding a guy who was the league’s best running back in 2013 and who turns just 27 in July seems like a reasonable way to improve a running game overnight, especially if it comes in combination with a free-agent bid for somebody like 49ers guard Mike Iupati, who played under new Bills offensive coordinator Greg Roman in San Francisco.

You have to wonder why the Bills keep coming back to this well. As the league has rapidly moved away from valuing running backs as big-ticket commodities, Buffalo appears to have missed the memo. Although the moves have come under different personnel departments, the Bills have repeatedly been disappointed with their aggressive moves for running backs.

It has been more than a decade of disappointment, actually. In 2003, the Bills spent a first-round pick on injured University of Miami running back Willis McGahee, who averaged 3.9 yards per carry before bad-mouthing the city on his way out of Buffalo, netting two third-round picks and a seventh-rounder from the Ravens in 2007. Next, the Bills spent the 12th overall pick in that year’s draft on Marshawn Lynch, only to erode Lynch’s confidence and value before dealing him to Seattle for fourth- and fifth-round picks. Disappointed by Lynch, they spent the ninth overall pick in the 2010 draft on C.J. Spiller, who packaged a wildly impressive 2012 campaign inside a five-year Buffalo career marred by injuries and inconsistency.

While those backs are all talented, they haven’t gotten the most out of their ability in Buffalo. Buffalo’s best back over much of that stretch has been Fred Jackson, an undrafted free agent who fellow Coe College alumnus Marv Levy signed out of NFL Europe. Given that the Bills have had no success committing significant assets toward running backs and have found a keeper in a guy nobody else wanted, doesn’t it seem like it might be worth going down that latter path again? Surely Coe must have produced a running back or two since Jackson left school.

Then again, the risk for the Bills, beyond the opportunity cost of dealing Alonso, is not especially high. After the trade, the Bills will have McCoy on a three-year, $25.3 million deal with just $1 million of that money guaranteed. If McCoy gets injured in 2015 or fails to live up to expectations, they can get out of the contract without any penalties. It’s still a hefty contract for a running back — the franchise tag figure for running backs is $10.9 million, right around McCoy’s cap hit of $10.25 million — but the Bills retain virtually all of the leverage.

The other opportunity cost for the Bills comes in 2016. If the Bills have a priority beyond acquiring a quarterback, it’s extending star defensive tackle Marcell Dareus, who is entering the final year of his rookie deal. Dareus is likely eyeing the record-setting contract Suh is about to receive as the baseline for his new deal, and while the Bills only have $96 million committed to the cap in 2016, every little bit counts. McCoy, whose 2016 cap hit is $7.2 million, is penciled in to have the second-largest cap hit on the team next season.

They can afford both, but when Dareus gets his massive raise, it becomes even more important for the Bills to find value elsewhere. If McCoy is merely a good running back and not the transcendent player he was in 2013, the Bills won’t be getting a worthwhile return on his contract.

What about Kiko Alonso?

It feels like Alonso is being sold short in the analyses I’ve read. Sure, a good chunk of why the Eagles made this trade has to do with dumping McCoy’s salary. Suggesting that Alonso is some spare part or that Kelly is only interested in Alonso because he coached him at Oregon is also unfair. Alonso has a chance to be a Pro Bowl middle linebacker over the next several years, and he could very well provide more positional value than McCoy in the years to come.

We’re almost two years removed from the best stretch of Alonso’s brief career, when he began his professional run in Buffalo with four interceptions and a sack during September of his rookie season. That was always going to be unsustainable, but we saw what Alonso was capable of during that stretch. He was a rangy, speedy linebacker built to play in the modern NFL, where middle linebackers have to be quick enough in short distances to close on the drag routes in front of their zones while simultaneously having enough long-range speed to carry faster tight ends and even some wide receivers up the seams. Alonso can be that sort of player in Philadelphia, and the Bills will miss him, especially as a nickel and dime defender.

Part of Alonso’s allure, as mentioned earlier, is that he works cheap. The former second-round pick still has two years left on his rookie deal, which will pay him $795,546 in 2015 and $991,418 in 2016. Those are bargain-basement prices for a talented young linebacker. Because Alonso missed all of 2014 with a torn ACL and spent the season on the non-football injury list, his contract also dictates that he will become a restricted free agent after the 2016 season as opposed to the vast majority of second-round picks from his class, who will become unrestricted free agents. Barring the unexpected, that gives the Eagles three cost-controlled years from what appears to be an above-average young linebacker.

It’s a lot to give up, but part of the logic unquestionably goes back to Rex Ryan’s ability to develop young defensive talent. Even with fellow middle linebacker Brandon Spikes an unrestricted free agent, the Bills are deep at linebacker with 25-year-old Nigel Bradham and 22-year-old Preston Brown, who impressed in Alonso’s absence. It wouldn’t be a surprise to see the Bills draft an inside linebacker or sign somebody like David Harris, Ryan’s former run-thumping inside linebacker in New York. If the Bills trust that Ryan can get more out of defensive players than he can out of similarly talented offensive ones — and that’s fair to say after his time in New York — it’s smart for them to leverage that and deal some of their defensive products for offensive weapons.

Alonso’s ACL injury also looms large here. ACL repairs and recoveries are commonplace in the NFL these days, but only the Bills are aware of just how well Alonso’s recovery has gone and how sturdy his knee is, especially if the trade really was put together in 20 minutes. Even if Alonso can pass a physical, he might very well be more susceptible to future ACL tears, and there’s no guarantee he’ll come back as the player he looked like during his rookie season. Those aren’t reasons to get rid of a player, but in assuming the risk of the McCoy contract, the Bills are shedding some of the risk that Alonso isn’t the player he used to be.

The flip side of it for the Bills, I suppose, is that they really didn’t need to trade Alonso if they wanted a running back. Murray is a free agent who would probably take $24.2 million over three years if the Bills offered it. Peterson might be a free agent soon. Ryan Mathews and Justin Forsett and a bunch of second-tier backs are out there. McCoy’s probably the best guy out of that bunch if you wanted to pick one over the next three seasons, but wouldn’t you rather have Forsett and Alonso than McCoy and a question mark at linebacker?

Is Kelly going overboard on this whole Oregon thing?

It’s hard to say. Alonso will become the ninth Oregon player on Philadelphia’s roster, which is sort of staggering, but he’s also very clearly the highest-profile and most important Oregon product of the bunch. Most of the Oregon players Kelly’s brought in are special-teamers and fringe contributors like Jeff Maehl, Kenjon Barner, and Taylor Hart. The only Oregon alum on the Eagles roster to suit up on more than 20 percent of the offensive or defensive snaps last year was Casey Matthews, whose arrival in Philly actually precedes Kelly’s time in town.

Given that the pool of replacement-level players competing for the last few spots on an NFL roster is enormous and likely impossible to sift through with any sort of reliable ability, there’s something to be said for focusing on a particular archetype and using that to emphasize some of the things you can control. Bringing in Oregon products to fill the back end of the roster gives Kelly players who are familiar with his intense practices and guys who are likely to be onboard with the program without raising much of a stink.

It’s a mistake to take those guys and have them fill meaningful roles — that’s where Steve Spurrier went wrong in Washington, if we can identify one of the many ways where Steve Spurrier went wrong in Washington — but up to this point, Kelly really hasn’t done that. Now, with personnel power, he’s gone out and acquired a former Oregon star to play a meaningful role on his team. It’s possible this is a one-time thing, that Alonso was a useful player at a position of need who just happened to come from Kelly’s college program. It’s also possible that the Eagles could become Oregon East in a more meaningful way in 2015. With Kelly winning his power struggle against Howie Roseman this offseason, we’ll see what happens in the seasons to come.

So, who won?

I don’t think it’s quite as clear as some might make it out to be, but ask me to pick a winner today and I think the Eagles came out on the better end of the deal. Expensive running backs just aren’t a valuable proposition in the NFL, and while McCoy does things at times that I can’t even fathom other human beings are capable of doing, he’s been inconsistent and probably isn’t worth the money remaining on his deal. Alonso is a three-down linebacker who is going to make pennies for the next three years; even if he’s just an average NFL starter, unless McCoy returns to his 2013 form, that’s a win for the Eagles.

And who lost?

More so than the Bills, I’d be worried if I were Murray or Peterson. Alonso is a talented player, but it’s sort of scary that the Eagles could shop around McCoy and only come away with a middle linebacker who missed 2014 with a torn ACL. It speaks to what little appetite teams have these days for spending big money on running backs; even teams with little hope at the position and plenty of cap space to spend, like the Raiders and Browns, didn’t appear to be interested in sending an asset to Philadelphia for McCoy.

The rule of contracts is simple: You pay a player for what he’s going to do, not what he’s done. More and more, teams are realizing that contracts for veteran running backs confuse the latter for the former. The Bills are hoping that what McCoy has done is proof that he’ll keep doing it.