49ers’ Trent Williams likely out 4-6 weeks with high ankle sprain, per Shanahan

Trent Williams' absence estimated at four to six weeks, but 49ers hold off on placing him on injured reserve.

Trent Williams could be out four to six weeks with a high ankle sprain, but 49ers coach Kyle Shanahan said Monday he’s not a lock for the injured reserve list.

Williams was injured in the third quarter of Sunday night’s 11-10 loss to the Denver Broncos and left the field under his own power after rejecting a ride in a cart to the locker room.

“He’ll be out some time,” Shanahan said on a conference call with local writers. “The swelling’s pretty bad. Usually for high ankles, for everyone, it’s four to six (weeks). Sometimes it can be sooner, sometimes it can be longer. That’s why we can’t give an exact date. It’s too early to tell.”

If Williams were to go on injured reserve, he would be out a minimum of four weeks. Shanahan said the 49ers weren’t ready to make that call since teams can make eight moves during the course of the season from I.R.

“We’re hoping we don’t have to,” Shanahan said. “You only get so many of those, so it’s like Ty Davis-Price (who sprained an ankle last week but was not placed on I.R.). If it ends up being longer we might have to make that decision.”

Players whom the 49ers expect to return include safety Jimmie Ward, possibly next week, and running back Elijah Mitchell in November. Defensive tackle Jordan Willis, who had knee surgery in what was termed a “cleanup” procedure, could also come back at some point.

The 49ers used second-year tackle Jaylon Moore for seven snaps after Williams departed. Moore gave up two quick pressures and Colton McKivitz came off the bench for the final 11 offensive snaps.

Shanahan said McKivitz would be the likely starter Monday night against the Los Angeles Rams and would have been first off the bench against Denver if he’d had a full week of practice. Daniel Brunskill could return to practice after missing time with a hamstring strain, but Shanahan said he would likely play at guard or center.

The season is only three games old, but the 49ers went into it without Ward, who strained his hamstring during a light practice heading into the opener and will spend his fourth game this week on I.R.

Tight end George Kittle missed the first two games of the season with a groin injury before returning to play against Denver.  Mitchell is on injured reserve and out until November with an MCL strain sustained in Week 1 against the Bears, and quarterback Trey Lance went out for the season with a broken right fibula in the second game against Seattle.

The 49ers also lost linebacker Azeez Al-Shaair, who departed the Denver game with an MCL injury that Shanahan was similar to that of Mitchell’s, meaning he’ll be out approximately eight weeks. The length of time Al-Shaair is out could make him more of an I.R. candidate than Williams.

Also missing the Denver game was defensive tackle Arik Armstead, out with a foot injury that NBC Sports Bay Area reported was plantar fasciitis. The 49ers gave up a little at the end, but held up well along the defensive front in Armstead’s absence.

“Without a doubt, the defense played well enough to win,” Shanahan said. “But it would be real nice to get Arik back this week.”

Surprise factor missing with Deebo

While Shanahan was able to spring Deebo Samuel as the “wide back” on the rest of the league last season when lining him up in the backfield, it’s been a different story through three games.

Samuel has 12 receptions for 131 yards and 17 rushes for 111 yards but is getting plenty of attention.

“We’re not surprising anybody, that’s for sure,” Shanahan said. “They know what he can do. That always makes it harder when you can’t surprise the league because everybody knows how good he is.”

Samuel caught a 32-yard pass that was a potential 68-yard touchdown if he hadn’t had to slow to catch the ball. Garoppolo missed him on a first-half pass in favor of an incomplete attempt to Brandon Aiyuk that could have been a touchdown as well.

“I still believe in a number of those plays, Deebo’s got a chance to get a big one,” Shanahan said.

The safety revisited

Shanahan took ownership of the call to have Jimmy Garoppolo throwing deep out of his own end zone for a shot play that ended in a safety. Garoppolo was pressured by former 49ers defensive tackle Mike Purcell and drifted across the back line of the end zone.

“Tried to take a big shot on that, and if it wasn’t there — which it wasn’t — we have some spots to ditch it,” Shanahan said. “We put him in a tough spot there where we didn’t pick it up inside like we planed on and it put him in a very tough situation with the nose not being blocked.”

Jimmy G’s tired arm, Kittle’s return

Shanahan didn’t hear Garoppolo talking about a tired arm Sunday night or needing to get in “game shape,” but he didn’t sound surprised.

“It’s the same for any player that didn’t do preseason,” Shanahan said. “It takes time for guys to get into game shape. You don’t simulate games on a practice field, that happens in games. I think that will come sooner rather than later. If he said that I’m sure he was tired as the game went, but we’ve just got to get him practicing more and in games more to get him in game shape.”

The same goes for Kittle, Shanahan said.

“George, he did some good things, but he’s not there yet because he hasn’t been playing much,” Shanahan said. “It was nice to get him back at practice last week and get him through the game healthy.”

Lenoir shines at nickel

Second-year corner Deommodore Lenoir played 35 snaps at nickel corner in place of rookie Samuel Womack III and he’ll likely stay there based on his performance against Denver.

Lenoir was credited with five tackles, including one for loss, and a pass breakup.

“We’re always going to put the best people out there that we think gives us the best chance to win and from the last few weeks watching practice, we felt that was Demo,” Shanahan said. “I was happy with how he played too. I thought he was one of the better guys out there last night.”

Quick hits

— Garoppolo’s lost fumble in the third quarter was a miscommunication with center Jake Brendel.

“Everyone went on one and Jake snapped it on two,” Shanahan said.

— Players had Monday off, and will meet for film review Tuesday. They will take Wednesday off, then begin preparations for the Rams on the practice field Thursday.

— Special teams continue to be an area of improvement under coordinator Brian Schneider, who replaced Richard Hightower. Following the Garoppolo safety, the 49ers managed to keep Denver at the 19-yard line following Mitch Wishnowsky’s free kick.

“That’s very rare after a safety,” Shanahan said. “They usually get good field position.”