Robert Williams has setback in concussion protocol, Romeo Langford a non-contact participant

For Robert Williams, his progression through concussion protocol started all over again Friday.

Williams, who sustained a concussion after catching an elbow from Kevin Love in the face while battling for a rebound early in Tuesday’s preseason finale against the Cleveland Cavaliers, spent Thursday’s practice riding a stationary bike, but he didn’t advance any further, feeling the effects from his concussion.

At Friday’s practice, Williams was seen walking on a treadmill with the C’s medical staff keeping a close eye on him as he works his way back.

“He didn’t feel great after yesterday, so they dialed him back, so he’s on day one again,” said Celtics coach Brad Stevens. “We’ll see how he feels after today. That’s the way that progression works. He’s at the early stages of (concussion protocol).”

The second-year center out of Texas A&M is set to have an elevated role this season — Williams played in just 32 games during his rookie campaign — due to the C’s lack of big man depth.

It looked as though Williams, who earned the start in Boston’s first preseason game versus the Charlotte Hornets, would be splitting the lion’s share of minutes with Enes Kanter and Daniel Theis given his unique skillset.

“All those bigs are important for us right now,” Stevens said. “Obviously Robert’s important from the standpoint he’s a young player, who I think has gotten a lot better. We need his something different that he brings to the table and that’s his bounce and athleticism at the rim and just continue to grow. He’s done a good job. He had a tough preseason game, game one, but everybody has an off day occasionally.”

Also on the injury front, Stevens had more encouraging news on rookie forward Romeo Langford,

It’s been an injury-filled preseason for Langford, who suffered a right knee sprain in the C’s third preseason game and missed Tuesday’s tilt against the Cavs. The Indiana University product has also dealt with a groin strain and his recovery from surgery on torn ligaments in his right thumb during camp.

“Romeo actually did some of the non-contact portion of practice today,” Stevens said. “Moving pretty well. Looks pretty good. We hope that he’ll be cleared for at least full practice by Monday.”