An interesting question came in this week from Bob in Dallas, who asked how I would rank the top quarterbacks for the next three years. The reason this is such a compelling debate: All of the top 10 quarterbacks last season in QBR are currently in their 30s.

Pretty remarkable, no?

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Bob lists his top eight as Aaron Rodgers, Andrew Luck, Ben Roethlisberger, Eli Manning, Tony Romo, Russell Wilson, Philip Rivers and Matt Ryan. Obviously, he omitted Tom Brady, Drew Brees and Peyton Manning with an eye toward the future.

Manning's stats dipped toward the end of last season. Was it injury or age? We'll find out this year. Brees may be starting to show signs of slowing down, but his game remains strong. And Brady, lest you forget his Super Bowl run, is as good as ever.

Of the three, Manning's future is the most cloudy. This could be his last season, even though you know he would love to play for two or three more years.

Factoring in age and projected decline, let's review my top eight for the next three years.

2015: 1. Rodgers, 2. Brady, 3. Luck, 4. Roethlisberger, 5. Manning, 6. Brees, 7. Rivers, 8. Wilson.

(In case you're wondering, Ryan would be my No. 9, followed by Eli Manning and Joe Flacco.)

Luck is No. 3 because he has carried the Colts to the playoffs in each of his three seasons, getting closer to the Super Bowl each time. Roethlisberger has worked well with offensive coordinator Todd Haley to get his passing stats up to 4,952 yards last season. Peyton Manning's dip late last season caused him to fall outside of the top four. Brees doesn't have Jimmy Graham and Kenny Stills, so it's not outlandish to suggest his numbers will fall off a bit.

2016: 1. Rodgers, 2. Luck, 3. Brady, 4. Roethlisberger, 5. Brees, 6. Wilson, 7. Ryan, 8. Flacco.

Where is Rivers, you ask? If the Chargers move to Los Angeles, I could see Rivers giving up football entirely, opting to coach and spend more time with his family. Rivers wants to remain a Charger, but only if the franchise remains in San Diego. Still, it might be hard for him to turn down an exclusive franchise tag at $25 million next season. For conversation's sake, I'm taking him off the list. Obviously, Peyton Manning would still be in my top eight if he opts against retiring. But as I said earlier, that's a big if.

2017: 1. Rodgers, 2. Luck, 3. Roethlisberger, 4. Brady, 5. Wilson, 6. Ryan, 7. Flacco, 8. Cam Newton.

Brady turns 40 in the summer of 2017. I have no doubt he still will be playing, but you figure his game would have to show some signs of decline. Brees, who will be 38 in 2017, falls off the list entirely. Where did Newton's name come from? He's good now, and I expect him to continue improving in each of the next three years.

Drew Brees might not be a top QB for long. AP Photo/Charles Rex Arbogast

From the inbox

Q: The Eagles made the blockbuster trade in acquiring Sam Bradford and his big salary. Everyone is insisting that if he's healthy, he'll be the starter. But Mark Sanchez, who has the most experience both in the NFL and Chip Kelly's system, has everyone raving in the Eagles OTAs. Do you think there is a legitimate chance Sanchez will win the starting job?

Nick in Clementon, New Jersey

A: A week ago, I picked Ryan Fitzpatrick as my No. 1 backup quarterback ahead of Sanchez. I made the selection figuring Brian Hoyer, Josh McCown and Matt Cassel will win starting jobs this summer. Arguably, they would all be ahead of Fitzpatrick if they were considered backups.

But to answer your question, yes, Sanchez has a chance to win the job, but my money is on Bradford as long as he doesn't have any setbacks coming off the ACL injury. Even though Sanchez has more experience in Kelly's offense, Bradford ran a spread attack very effectively at Oklahoma.

Bradford hasn't been doing the 11-on-11, but he still has the edge over Sanchez because he has more of a tendency to go downfield with his throws. What no one can take away from Sanchez is how well he did in Kelly's offense last season.

In eight starts, he averaged 30 points a game, compiling more than 30 on five occasions. His 63.8 completion percentage was more than respectable considering he was a 55.1 percent thrower with the Jets. His 2,216 yards in eight games in 2014 would put him on pace for a 4,432-yard season. As a Jets starter, he had only two seasons of 3,000-plus yards.

Sanchez's play last season was hard evidence that Kelly's system does indeed get the most out of a quarterback.

Mark Sanchez has a chance to win the starting job in Philly, but Sam Bradford is the favorite. AP Photo/Kathy Willens

"He's just so much more comfortable in terms of what we're doing," Kelly said of Sanchez at the conclusion of minicamp. "Last year he was coming off an injury, coming off missing a year, probably wasn't a hundred percent when we were with him last year at this point in time. He was learning a new offense on the fly. So there's a whole different comfort level when you see Mark out there now."

Kelly said Sanchez knows where his No. 2, No. 3 and No. 4 receivers are and that he understands the protections better.

Like Sanchez last season, Bradford is coming off a year in which he didn't see the field. Unlike Sanchez, he has a good knowledge of the protections because of his experience with the college spread. As long as he's healthy, Bradford has the look of a quarterback who can put up a 4,500-yard season and score a bunch of points.

Kelly needs them both, which is why he's in good shape at the quarterback position. Spread quarterbacks tend to get hit and suffer injuries. If that happens to Bradford, Sanchez can again prove his worth as a backup.

Q: Every offseason, I read about teams releasing players from contracts that went unfinished. While I don't agree with his circumstances, Adrian Peterson had a point about teams having more power than the players when it comes to contracts. I feel like the system is designed to be against the players, especially when you consider the concept of a franchise tag. Am I missing something here?

Bruce in Dallas

A: There is no doubt that the current system favors teams more than players. It's becoming harder and harder for players to get the leverage to get full skill guarantees in their contracts. Most of the time, a good portion of a player's guarantees are for injury only, which means the team can cut him and not have to pay the remainder of his contract. Only the top free agents and quarterbacks receive guarantees that last until the second and third years of their contracts. You watch: Next offseason a handful of well-paid free agents will be cut to free up cap space. Peterson does have a point, but the issue won't be fixed until the next collective bargaining agreement is negotiated.

Q: My question is in regards to the Chargers leaving San Diego. I feel as if they have already made up their mind and will try to leave.

Adam in San Diego

A: Dean Spanos has been patiently waiting for the area to present a workable deal to keep the team in San Diego. But time is running out. Odds are favoring the team leaving because of the development in Carson, California. The two most recent meetings didn't go well. The first proposal wasn't enough, and the second idea of having a Dec. 15 vote comes too late in the process. Remember, Spanos is a businessman. He and his family can't afford to take a subpar deal to stay because he might have to compete for fans against two other franchises moving into Los Angeles. For it to work in San Diego now, Spanos needs a solid proposal. There is still time to get something done, but it doesn't look good for the Chargers staying in town.

Q: With the NFL's desire to expand the season from 16 games to around 18, more players will be needed to fill in the gap to compensate for injuries. Most teams are already signing players off the streets deep into the season when they cannot find anyone on the practice squad. You have suggested in the past that a developmental league would be helpful, but hasn't that already been tried with the now defunct NFL Europe?

Patrick in Seattle

A: It has been tried and it needs to be tried again. Things have changed since NFL Europe was around. Missed starts because of injuries have increased each year. Teams aren't taking the risks with players who suffer concussions. Spread offenses in college have created tougher transition periods for quarterbacks and other players turning pro. I'm confident the league will work out some kind of development plan in the next couple of years. The NFL needs it.