Shaun Hill will start Sunday for the winless Lions at home against the St. Louis Rams.
Stafford hasn't played since he injured his right shoulder in the season-opening game at Chicago.
Schwartz says Stafford has begun to throw and his rehabilitation is on schedule. The team hasn't provided a timetable for Stafford's possible return.
The No. 1 pick in the 2009 draft has played in 11 games and will miss his 10th when he watches Detroit face St. Louis about a month after his latest injury.
Hill has completed 60 percent of his passes for 991 yards with five touchdowns and seven interceptions in four games this season.