Harty has been a good returner for the Bills this season, as he's averaging a little over nine yards per return, but nothing that's blown anyone away. Harty is rarely used in the offense and needs to try and be an impactful special teamer if he wants to keep his spot on the team. However, Harty had a costly fumble in the first quarter last game which helped put the Chargers ahead by 10 points and overall shifting momentum.
Harty is in no position to make a mistake like that, especially when there are players like Andy Isabella on the practice squad and even Leonard Fourtnette, who's starting to field kicks. Harty can't afford to make any more mistakes like that, or else his job is in real danger.
Kincaid is another player who's had a stretch of success with the Bills but has rarely been a factor since then. Ever since the return of Knox, he's rarely been a factor and used more as a blocker. Kincaid hasn't been too consistent as a receiver, as he's had some bad drops during the season, which shifts to the veteran Knox getting more targets rather than the rookie.
Kincaid has had his fair share of dropped passes recently, which is a little concerning due to his given role in this offense. Although there can be some benefit of the doubt, given that he's a rookie and is still having some growing pains. However, the offense needs him in some upcoming games, maybe even this one against the Patriots if Diggs or Davis don't become big factors in the passing game.