It never seems like the right time to trade a surprising producer. But the question is, can they keep it going? If they're this year's version of 2019's Lamar Jackson or Austin Ekeler or DeVante Parker--guys putting up big numbers based on conditions that won't likely change--then your opponents probably won't offer you what they're actually worth.
Other guys are in situations we know will change. For example, Mike Davis has been a fantastic contributor, but his value is about to tank, as CMC is expected back after this week. So of course the only way you're getting decent value for Davis is if you trade him to someone desperate for a Week 5 win (a smart move, of course).
Then there are great producers who are expected to keep rolling all season. Except they're bigger risks than most people expect, meaning it's better to cut bait now than risk losing their value. Here are the players I'd sell high as soon as possible:
At QB, Joe Burrow is currently the #9 scoring fantasy quarterback. In most one-QB leagues, I'm not sure you can do much with him, since there should be plenty of QB2s on waivers who can produce similar numbers the rest of the way. But in two-QB leagues--or in very deep one-QB leagues--he's a regression candidate. Four of his next six weeks he's facing the Ravens, Colts, Steelers, and a bye. While his schedule softens later, he'll get Pittsburgh again Week 15. The point is, most of the next six weeks he probably won't be a top-14 option, and he might not even be in the top 18. I'd sell high now.
There are so many running backs to choose from, though today I'm not interested in guys who are obviously on their way down based on the imminent return of starters--like Jerick McKinnon or the previously mentioned Mike Davis. Instead I'll say the 11th-ranked Melvin Gordon. With or without Phillip Lindsay, Gordon isn't an RB1. But when Lindsay returns, Gordon will be a tough sell even as a mid-range RB2, and his fantasy playoff schedule (the Bills and Chargers weeks 15 and 16) aren't encouraging. There's not enough juice in this offense, and too much backfield talent, to keep Gordon from falling through the rankings.
At WR, several guys concern me, including Amari Cooper as an elite wideout (there's too much talent in that corps to keep Amari at or near #1) and Calvin Ridley (a healthy Julio will level things out a bit). But my bigger concern is with #5-ranked Stefon Diggs. Diggs has done most of his damage against the Jets, Dolphins, and Raiders. Starting in Week 11 he'll face a bye, the Chargers, Niners, Steelers, Broncos, and then the Patriots Week 16. If I sell him for mid-range WR1 value, I'm thrilled.
At TE, Robert Tonyan (#2) appears obvious, though there are so many short-term factors impacting his rise and probable fall, including the health of Davante Adams and perhaps Allen Lazard. Monday's outburst was a perfect storm. Let's table debate on him for now. Instead, let's turn to T.J. Hockenson (#10). In deeper leagues, he could be useful trade bait to those stuck without a top-16 tight end. But with Kenny Golladay healthy, an improved backfield, and Matthew Stafford on pace for only 548 attempts (which would be a per-game career low), Hockenson's ceiling is capped.