Two offseasons ago, James Shields was seeking a five-year deal worth $125 million. He went unsigned until February, and ended up settling for a four-year deal worth $75 million in San Diego. One year and four months later, the Padres are paying more than half of Shields’ remaining salary for him to play on another team.

The deal goes like this:

So the full deal — James Shields and cash for Erik Johnson and Fernando Tatis Jr. — is what @barstoolWSD originally reported. Nice work. — Dennis Lin (@sdutdennislin) June 4, 2016

The funny thing about the White Sox rotation is that it was both excellent and also in obvious need of an upgrade. Prior to acquiring Shields, our rest-of-season forecasts actually had the White Sox rotation as the sixth-best in baseball, but it’s been clear for a while now that they’d eventually need to do something to address the back-end. Those same forecasts expect a 3.49 ERA and a 3.40 FIP from Chris Sale, Jose Quintana, and Carlos Rodon, which is elite. The rest of the rotation, though? The rest of the rotation, which would be expected to account for 40% of the team’s starts, was projected for a 4.85 ERA and 4.79 FIP.

So they went and acquired Big Game James, and with Shields, the White Sox rotation has added another win to its rest-of-season projection, but more importantly, has lengthened the depth. The sixth starter is now either Latos or Gonzalez, rather than Johnson, whose former prospect shine may have officially worn off sometime between last year and now. And if all goes well, neither will be tasked with starting a playoff game. The White Sox announced their presence as a contender by getting off to a 23-10 start, and now, they’ve filled out an actual playoff rotation.

From the Padres’ perspective, Shields was nothing more than a trade chip. He’d been largely underwhelming since joining the National League, putting up an adjusted ERA seven percent below league average in San Diego, and an adjusted FIP 14 percent below league average. That they had to eat more than half his remaining salary shows just how far Shields’ value has dropped. What they received in return further reinforces that notion.

Johnson is a former second-round pick with a career 4.50 ERA and 5.68 FIP in 98 big-league innings. As a 26-year-old this season, he’s posted a 5.31 FIP in 10 starts between the majors and Triple-A, displaying neither velocity nor command. The highlight of the package is Fernando Tatis Jr., son of the other Fernando Tatis, a 17-year-old infielder signed for $700,000 out of the Dominican Republic last July. A total wild card. Could be a future All-Star. Could be a future zero. The bigger point is that San Diego doesn’t owe James Shields his full salary in 2017 or ’18 anymore, and maybe possibility potentially they’ve received some future talent for that right. This is what it looks like when a team swallows its pride and trudges forward.

The most glaring issue that’s depreciated Shields’ value over his last 44 starts has been the long ball, and with that in mind, moving from Petco Park and the National League to US Cellular Field and the American League is a frightening proposition. Starting last year, Shields has allowed one of the five-worst home run rates by an active qualified starter. Petco suppresses homers by 2%. US Cellular boosts them by 8%.

The more subtle way that Shields has declined, though, is that he’s putting more batters on base with free passes — less than ideal when giving up as many long balls as Shields has. In 2015, Shields doubled his walk rate from the prior season. Since the start of 2015, he’s thrown the third-lowest rate of in-zone pitches among all qualified starters. As we’ve seen with Francisco Liriano, this is a style (intentional or otherwise) that can work well when executed, but the league is adjusting back to the extreme out-of-zone pitcher, and Shields is no exception — he’s seen the 10th-largest decrease in out-of-zone swings from any qualified starter last year to next.

More concerning is the potential explanation for Shields’ shift in approach. He didn’t always work out of the zone like this, see. In fact, in every year of his career until coming to San Diego, he ran roughly average in-zone rates. But last year’s extreme shift toward working outside the zone coincided with a 1.4-mph drop in velocity — the first time he’d ever experienced a downtick in velo, and an indicator that perhaps Shields was no longer comfortable working inside the zone with diminished stuff. He’s lost another tick of velo this year, and is now down more than two miles per hour from where he was in his Kansas City days.

Essentially, Shields has lost velocity, and it’s caused him to work outside the zone. But hitters aren’t chasing outside the zone, so he’s giving up walks, and when he’s forced to come inside the zone, he’s giving up dingers. It’s not a particularly promising series of events.

But here’s the thing. Shields has always had a reputation as a frontline starter, a reputation he earned. In Kansas City, he was expected to be that. In San Diego, he was expected to be that. He’s not that anymore, but the nice thing is that in Chicago, he isn’t being asked to be. He’s a third or fourth starter who only needs to be a third or fourth starter, and that’s not too bad. Assuming Shields doesn’t exercise his opt-out after this season, the White Sox will be on the hook for roughly $26 million over the next two years, so they’re hoping the decline will at least somewhat plateau, but that’s not an exorbitant sum given Shields’ ability to eat innings as a league average-ish starter.

The White Sox upgraded their 2016 roster, and especially so when you consider the potential of postseason play. Far as Shields has fallen, he’s still an improvement over the likes of Mat Latos, Miguel Gonzalez, and Erik Johnson, and now if the White Sox find themselves playing October ball, they should certainly expect to feel more confident in Game 4. They gave up very little in terms of talent to acquire Shields, and with the Padres sending $30 million their way, his remaining salary no longer infers frontline production, but instead reflects what he actually is.