Purdy (shoulder) is listed as active Sunday at Buffalo, Lindsey Pallares of the 49ers' official site reports.
Prior to sitting out last Sunday's loss at Green Bay, Purdy barely threw as he dealt with soreness in his right throwing shoulder. He kicked off Week 13 prep in a similar manner to one week prior, but he progressed enough as the week went on to log a full practice Friday and have coach Kyle Shanahan state that the quarterback would return to action Sunday, per Nick Wagoner of ESPN.com. Still, Purdy carried a questionable designation into the weekend. Late Saturday, Adam Schefter of ESPN reported that Purdy didn't endure any setbacks Friday or Saturday and was expected to reclaim his starting gig, which now has been confirmed. The 5-6 49ers must win to keep pace in the NFC West, as the Seahawks took down the Jets on Sunday to get to 7-5, the Cardinals lost at Minnesota to fall to 6-6, and the Rams won in New Orleans to improve to 6-6. As a result, Purdy's presence is key for San Francisco's playoff push.