Brady was limited in practice Friday with an ankle injury and was listed as questionable for Sunday.
The 37-year-old has not missed a game since 2008.
Last week, Brady threw for a season-high 292 yards and two touchdowns in a win over the previously-undefeated Cincinnati Bengals. In Week 4, the Patriots lost 41-14 to the Chiefs and Brady threw two interceptions and was replaced in the fourth quarter by rookie Jimmy Garoppolo.
On the season, Brady has completed 60.5 percent of his passes for 1,083 yards, six touchdowns and two interceptions in five games.
It was recently reported that personnel and coaching changes have led to tension between Brady and the New England coaching staff. The rift could reportedly lead to him finishing his career with another team.
New England is 3-2 heading into Sunday's game in Buffalo.
- Molly Geary