FOXBORO, Mass. — New England Patriots coach Bill Belichick on Wednesday offered a brief update on rookie running back Sony Michel, who has yet to take the field in his first NFL game.

A reported knee injury suffered early in training camp forced Michel to miss 12 practices and sit out all four Patriots preseason games. His status for Sunday’s regular-season opener against the Houston Texans remains in doubt.

“He missed some time, so he’s a little bit behind,” Belichick said. “But he’s working hard to catch up on and off the field in all areas.”

Belichick’s comments echoed those of Patriots running backs coach Ivan Fears, who said last week Michel remained limited in practice. Michel’s health appears to be improving, however, as he’s been seen participating in positional drills at each practice this week.

“He’s working at it,” Belichick said. “Getting better every day.”

Releasing veteran Brandon Bolden on cutdown day left the Patriots with four running backs on their 53-man roster: Rex Burkhead, James White, Jeremy Hill and Michel, the 31st pick in the 2018 NFL Draft. Burkhead also missed the preseason with a reported knee injury, but reports have indicated he’s expected to be ready for Week 1.