BOSTON -- Robert Williams (concussion protocol) isn’t the only Celtics big man dealing with a head-related injury.

Tacko Fall did not practice with the team on Saturday after getting hit in the head on Friday, according to coach Brad Stevens.

“He was a little under the weather,” Stevens said of Fall. “It sounds like, just being very cautious about that. So, we’re hopeful that … he won’t enter concussion protocol but if he needs to, he will.”

Fall, recently signed to a two-way contract by the Celtics, has been a major draw both at the TD Garden and on the road.

But more than that, the 7-foot-6 sensation has shown improvement in his overall game since the start of training camp.

The same goes for Williams whose third-year option for the 2020-2021 season was picked up by the Celtics.

The second-year big man entered training camp as a potential opening night starter for Boston, something that seems less likely now due to the time missed while in concussion protocol.

Stevens hinted that there’s a pathway that could potentially lead to Williams being cleared to play in the season opener at Philadelphia on Wednesday.

Williams is expected to work out on Sunday.

“From what I’ve heard, the next step after that is the non-contact portion of practice,” Stevens said. “And hopefully he can get through contact on Tuesday and cleared, but we don’t know yet.”

The only other injury of note involves rookie Romeo Langford, who suffered a sprained right knee injury in Boston’s 118-72 blowout win over Cleveland on Oct. 13.

He could be cleared to resume practicing with the team sometime next week.

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