The Bills placed Spector (calf) on injured reserve Tuesday.
Spector (calf) is doubtful to return to Sunday's game against New England, Alaina Getzenberg of ESPN.com reports.
Spector (calf) is active for Sunday's game against the Lions.
The Bills activated Spector (calf) from injured reserve Saturday, and he remains questionable to suit up for Sunday's Week 15 game against Detroit.
Bills head coach Sean McDermott said Wednesday that Spector (calf) is being designated for return from IR, Maddy Glab of the team's official site reports.
Spector (calf) is listed as questionable ahead of Sunday's matchup against the Colts.
Spector recorded five tackles (three solo) during Sunday's 31-10 win at Seattle.
Spector will start at middle linebacker Monday against the Jaguars, Joe Buscaglia of The Athletic reports.
Spector recorded 10 tackles (seven solo) during Thursday's 31-10 win over the Dolphins.
Spector (calf) was left off the Bills' injury report Wednesday ahead of the team's regular-season opener Sunday against the Cardinals.