One of the biggest wrinkles about dynasty fantasy football is knowing when to get out of a player's stock. Any time you can sell a player off his last (or nearly his last) big season, you’ll get a better return than you will if you wait until that first bad season.

With that in mind, let’s look at some players to consider selling this offseason while their stocks are still high instead of waiting for the bottom to drop out.

Quarterback

Matthew Stafford, Los Angeles Rams

Stafford has been old reliable for a long time at quarterback, but his offseason trade to the Rams has given him buzz he hasn’t had in a long time. And he could certainly follow through on that buzz in 2021, in an exciting new offense with an exciting new offensive coach. But he also just turned 33 and has had more injuries in recent years (albeit playing through most of them). Stafford’s fantasy value has long been derived by quantity as much as quality, and the presence of Cam Akers could cap Stafford’s pass attempts. The Rams’ penchant for mortgaging the future will come due at some point and result in less firepower across the roster … right? And man, his street value will never be higher than the excitement of now.

Running back

Christian McCaffrey, Carolina Panthers

McCaffrey played three games in 2020, scoring two touchdowns in each while putting up 28.5, 24.8 and 37.1 PPR points. That is absurd in about a dozen different ways, and it also keeps McCaffrey viewed as a pretty solid prime fantasy option despite the fact he only played in those three games. But we’ve also heard murmurs this offseason that the Panthers could be making massive changes this offseason, including at quarterback and (far-fetched as it may be) running back. And with McCaffrey hurt in 2020, the Panthers receivers — especially D.J. Moore and Robby Anderson — had big years. Even if McCaffrey is fully healthy in 2021 and going forward, his upside is never likely to be where it now again.

Derrick Henry, Tennessee Titans

Henry is a unicorn, so if you want to bet on him continuing to be as productive as he has been the last two years (1,540 rushing yards and RB5 in 2019, 2,027 and RB3 in 2020), it’s exactly as hard to argue against it now as it would have been before last year, and exactly as hard as it would have been before 2019. But Henry now has two of the six active RB seasons with 250-plus PPR points and no more than 250 receiving yards … and one of the other four belongs to Alfred Morris, for whom “active” is a pretty tenuous description (and the other three belong to Adrian Peterson, who also isn’t exactly the most active at this point). Guys with Henry’s profile can be productive for a long time, but they aren’t something you want to count on as top-five backs, especially with Henry now 27 years old.

Wide receiver

Cooper Kupp, Los Angeles Rams

The arrival of Matthew Stafford in Los Angeles should mean good things for the Rams' offense overall, simply because Stafford is a good quarterback. But his impact on Kupp could be a negative one. The 10 best pass-catcher fantasy seasons of Stafford’s Lions career (2009-2020) belong to Calvin Johnson (six times), Marvin Jones (twice), Kenny Golladay and Golden Tate (once each). Of those, only Tate is anything resembling a slot receiver. Stretch to the top 20, and you have four Tate seasons and one each from Brandon Pettigrew and T.J. Hockenson (two tight ends). Stafford’s average depth of target the last two years was 10.6 and 8.7 yards; Jared Goff’s was 7.7 and 6.2. There are already rumors of Jones, Golladay or some other field-stretching receiver joining Stafford in Los Angeles, further diminishing the upside of Kupp (and potentially Robert Woods as well).

Amari Cooper, Dallas Cowboys

Fourteen receivers have at least 1,200 PPR points since Cooper entered the league in 2015. Of those, Cooper has at least three more games (39 of 93, 39.8%) with 10 or fewer PPR points than anyone else on the list, and more than twice as many such games as seven of them. Only Brandin Cooks, Larry Fitzgerald and Stefon Diggs join Cooper in sub-10-point performances in at least a third of their games. The highs are high with Cooper, but the lows are painfully low, and further development from CeeDee Lamb and Michael Gallup could further eat into that. Per Fantasy Football Calculator dynasty startup ADP, Cooper is still going 10th at the position, and if that equates to anything like his trade value, it’s time to sell.

Tight end

Travis Kelce, Kansas City Chiefs

Dynasty players aren’t dumb, and it’s not exactly a secret that Kelce is 31 years old, but what would the asking price for him be right now? What could you command? No tight end has ever offered anything like the value Kelce offers right now, and that includes health — he’s missed two games since missing his 2013 rookie year with a knee surgery, and those were both meaningless Week 17 games. He has Nos. 1 (2020), 3 (2018) and 9 (2019) seasons all-time in tight end receiving yardage. Can he do it again in 2021? Probably! What about 2022 and beyond? Maybe! There’s no reason to expect Kelce, with the game’s best quarterback and an elite offensive coach, to fall off any time soon. Except that elite performance almost always does. Kelce’s trade value will never be higher. There’s no reason not to try to capitalize if you can.

Darren Waller, Las Vegas Raiders

Waller had 178 combined receiving yards in his first four years in the league. He has 1,145 and 1,196 in his last two. The path to Waller’s ascension has been a famously twisty one, so the point of that isn’t just to illustrate his enormous breakout, but also to note that Waller is older than you probably realize. He’ll be 29 in September, making him more than a year older than George Kittle. And with uncertainty at the quarterback position in Las Vegas and the potential for second-year development from the likes of Henry Ruggs and Bryan Edwards (and the potential return of Tyrell Williams) risking eating into Waller’s targets, you might be well-served to look for a trade partner before next season.