WR Vincent Jackson
Vincent Jackson is the favorite target of both Mike Glennon and Josh McCown, and opposing offenses know that. The result has been a relative lack of production outside of one game, and a heavy dependence on scarce touchdowns for his statistics. Opposing defense focus on taking Jackson away, and the Bucs have struggled to go elsewhere with the ball.
This is not very likely to change going forward, but Jackson's production isn't likely to stay this bad. He's been bothered by a broken wrist for part of the season, which should become less of a problem. In addition, catching fewer than half his targets is not a sustainable outcome for any receiver, regardless of how bad those targets have been.
Jackson had a simlar lack of produciton at the start of last season, with one good and three poor games over the first four weeks. That improved the rest of the way, though he was still a little inconsistent. Jackson likely won't be a number one receiver, but a low-end number two/high-end number three is probably what you can expect out of him going forward.
RB Doug Martin
Nope, he's done. The Bucs don't have the offensive line and blocking to consistently open up holes for him, they don't have the defense to keep the game close to give him more carries, and he hasn't looked good enough to continue to get a big workload. The team would like to run the ball a lot, they just haven't been and won't be able to do it.
Further ruining Martin's fantasy value: Charles Sims is likely to come back in week nine, and he should get a sizable role in the backfield. Sims is more explosive than Martin and a better fit for the zone blocking scheme the Bucs tend to run. And he's more talented as a receiver running routes downfield. The Bucs were really excited about him this offseason, and he'll make Martin worth even less as a fantasy back once he returns.
QB Mike Glennon
Glennon has actually been fairly productive in fantasy so far. I mean, not as a QB1, but he can be a useful bye-week fill-in or QB2. He hasn't been massively productive, but he's had some good games and the Bucs' inability to run the ball forces them to rely on his arm a lot. That gives him lots of room to pile up statistics, especially given the fact that his second-half incompetence last year has been flipped and he's been highly productive in the final two quarters of games.
One minor complication is Josh McCown. While it seems a little unlikely that he'll come back and take over as the starting quarterback once he's healthy, it's far from impossible -- and Lovie Smith has consistently refused to commit to Mike Glennnon as his starter.
WR Mike Evans
Evans is basically a more explosive version of Vincent Jackson who doesn't get thrown to as much. He has the potential to be very, very productive, but he's more likely to be stuck in the low-end WR3 role he's seen so far. As long as Glennon continues to focus on Jackson, Evans will simply not do much more than a handful of catches for 50-odd yards every game, and his viability as a fantasy player will rely on his red zone production.
TE Austin Seferian-Jenkins
His talent is undeniable and he's basically played every snap on offense over the past few weeks, but Seferian-Jenkins has struggled to be consistent and play fast. As he gets more comfortable with the game his passing game role and his production should expand, but I'd steer away from him until he actually starts doing that. There's a solid chance he just won't be a reliable performer at all this year.
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