DENVER -- After he lost a hotly contested preseason competition for the Denver Broncos' starting quarterback job, Drew Lock said he would prepare like he was the starter each and every week. He said he would work to get better at his craft. He said if his team needed him to step in he would be ready to do just that.

Those promises could be put to the test. Teddy Bridgewater suffered a concussion during the Broncos' 23-7 loss to the Baltimore Ravens Sunday. That puts Bridgewater in the league-mandated protocol to return to the field. He must now clear multiple benchmarks, each approved by a third-party physician, to return to conditioning work, then to noncontact position drills, then a full return to practice.

That could, depending on how the next few days go, put Bridgewater out of the lineup for the Broncos' game against the Pittsburgh Steelers and possibly beyond that.

"I'm not sure," Lock said Sunday following the game when asked how his week would go. "... I'm going to go about it like I'm going to start this week."

The Broncos were cruising along quite nicely with Bridgewater's patient and opportunistic play over the season's first three games. But there were early signs of trouble Sunday -- with the Ravens' penchant for pressure and the Broncos having backups starting at each guard spot.

Bridgewater threw a 3-yard touchdown pass to tight end Noah Fant 42 seconds into the second quarter to briefly give Denver a 7-0 lead, but he had already taken multiple hits both in and out of the pocket, including one in the first quarter that knocked off his helmet.

Then, on the Broncos' last play from scrimmage in the first half, Bridgewater was hit by Ravens linebacker Odafe Oweh on an incompletion.

He was examined on the sideline, then taken to the locker room before halftime. Lock said he was told Bridgewater would not return to the game just before the Broncos left the locker room for the start of the second half.

Trailing 17-7 at the break, things didn't get better for the Broncos under Lock. He completed 12 of 21 passes for 113 yards and an interception in his half of work.

Worst of all, the disjointed play that was all too common last season looked to have returned. The Broncos rushed for 73 yards in the first quarter, including a 31-yard run by rookie Javonte Williams when six different Ravens players had a chance to tackle him before the play was finished. They rushed for just 33 yards on only nine carries the rest of the game.

"His performance was just like the rest of the offense, it just wasn't good enough [Sunday]," said Broncos coach Vic Fangio of Lock. "... We couldn't get nothing going, we weren't getting it going with Teddy either after the touchdown drive."

"There's not many reps during the week when you're the backup, but that's my job, that's what I've got to be good at right now," Lock said. "I wasn't the best at it [Sunday]."

Lock said in the weeks since Fangio made the decision to go with Bridgewater he has tried to adjust to the schedule of the backup even as Bridgewater has continued to try to help him along the way.

"His biggest thing with me is working on footwork stuff," Lock said Sunday. "He'll stay after practice and put me and [No. 3 quarterback Brett Rypien] through footwork drills ... it means a lot, it's not like we're out there for five or 10 minutes, we're out there for like 20, 30 minutes at a time ... he's been really important to me these last couple weeks and I appreciate everything he's done for me."

Lock said he has worked with quarterbacks coach Mike Shula extensively. He said he also has gone through the plays the offense ran with Bridgewater in the previous game or in a previous practice on his own with the scout team receivers.

"After Week 1 you kind of realize what a backup feels like," Lock said. "... I think I can still keep getting better at what that is exactly."

In the next three games the Broncos will play at the Steelers (1-3), home against the Las Vegas Raiders (3-0) and at the Cleveland Browns (3-1) on a short week for "Thursday Night Football."

Lock suffered a shoulder injury last season in a Week 2 loss at Pittsburgh and said Sunday another start against the Steelers would "be a good chance to go back to Pittsburgh and put some of that to bed."

"We have the utmost confidence in Drew," safety Justin Simmons said. "It's unfortunate seeing Teddy go down, but it's a chance for us as a defense, Teddy's out, Drew's in, let's help him, let's give him a short field, let's get him a takeaway, let's get a three-and-out and have him back up ... things like that. Defensively those are the things you talk about on the sideline and [I] just don't think we did enough to help him toward the end of the game."