FOXBOROUGH, Mass. -- New England Patriots running back Damien Harris, who is projected to have a significant role, has been sidelined with a hand injury that could threaten his availability for the season opener, according to a league source.

Harris hasn't been at the Patriots' past two practices. He was primed to join Sony Michel as part of the Patriots' top running back duo, but that is now in question for the Sept. 13 opener against the Miami Dolphins.

NFL teams aren't officially required to report injuries until next week.

Patriots coaches have raved about Harris, the 2019 third-round draft pick who had a quiet rookie season after leaving Alabama as the school's eighth all-time rusher (3,070 yards).

"Damien has had a really good camp," coach Bill Belichick said this week on SiriusXM NFL Radio. "He came to camp in very good condition. He's taken a lot of reps. He's handled everything in the running game and passing game very well, which he did last year. I think everybody had a lot of confidence in him but they've all gained a lot more in him just because of his consistency and dependability."

Added running backs coach Ivan Fears: "From what we've seen, and the training camp he's had, I tell you what, he's pretty exciting."

Harris' absence from practice coincided with the Patriots activating veteran running back Lamar Miller from the physically unable to perform list on Monday. Miller is returning from a torn ACL that sidelined him for the 2019 season.

"You have to give him a chance to get his legs up underneath him and get back in the groove," Fears said. "We threw him in the fire pretty fast, just because we're running out of time where you can be very physical in practice, so we wanted to give him a little taste of getting bounced around a little bit. I really expect Lamar to bounce back and be the guy he was, but I'm sure that's going to take a little time."

Miller is vying for a roster spot alongside Michel, who had opened training camp on the physically unable to perform list but returned to practice Aug. 26. Michel underwent offseason foot surgery.

"He doesn't show any signs of slowing down from the injury," Fears said, adding that the 5-foot-11, 215-pound Michel worked hard to get his weight down after the surgery.

Passing back James White and versatile veteran Rex Burkhead are also key cogs at the position, while undrafted free agent J.J. Taylor (Arizona) is making a strong charge for a roster spot.