Josh McCown remained in the concussion protocol but attended meetings and watched film Monday, a day after suffering a concussion on a helmet-to-helmet hit in the first quarter. A league source said he felt good.

While that’s encouraging, coach Mike Pettine said the team began the week anticipating Manziel will get the start Sunday in the home opener against the Tennessee Titans.

“That’s accurate to say,” Pettine said. “If we have our starting quarterback in protocol … it’s an ideal situation that Josh would be back at the end of the week, but we have to plan otherwise that he won’t be available at least early for practice.

“We’ll see how it plays out. Johnny early in the week will get the starting quarterback reps.”

McCown, 36, has been No. 1 on the depth chart since he was signed in February and took virtually every repetition with the first-team offense during the offseason, training camp and the preseason. He’s well-versed in the scheme, so if he’s cleared at any point during the week he would presumably reclaim the job.

“We’ll make that decision then,” Pettine said. “We’ll just see how it goes.”

Manziel could use the snaps with the starters, even if he doesn’t get the call vs. the Titans. He stopped throwing Aug. 23 with a sore elbow and missed the last two preseason games, when he would’ve played a ton. He only returned to throwing in practice Sept. 7, and the rust showed as the game against the Jets progressed.

After throwing a 54-yard touchdown and posting a 149.3 rating in the second quarter, Manziel went 9-for-18 for 89 yards, an interception, two fumbles and a 41.2 rating in the second half.

“I think the hardest position in sports is quarterback, and I would argue that backup quarterback’s even harder if you’re tossed into the game,” Austin Davis said.

Davis was inactive Sunday as the No. 3 quarterback. He was signed Sept. 7 after being waived by the Rams in the final cut and clearing waivers.

If McCown isn’t cleared by an independent neurologist, Davis would be forced to step up to No. 2. He has experience playing in an emergency after going from No. 3 in the preseason to No. 1 in the opener last year for St. Louis. He went 3-5 with a 63.4 completion percentage, 2,001 yards, 12 touchdowns, nine interceptions and an 85.1 rating before being benched.

“The biggest thing is hopefully Josh is back and ready to go,” Davis said. “I think that’s what we all want.”

Despite Manziel’s inactivity leading up to the game, Pettine said the game plan wasn’t scaled back after McCown was knocked out at the end of the first drive.

“I mean, they’re responsible. That’s one of the reasons we do the repetitions from behind with the quarterbacks so they’re still getting at least the footwork rep and the mental rep of a play,” Pettine said. “It’s not the same as getting a play, but you’re still getting the repetitions in it, and that’s the challenge for the guys that are the twos in this league, is that they can function, they can operate a full game plan. You don’t want to have to scale it back, and we did not when he went in there.”

But the offense didn’t operate as smoothly as during McCown’s 90-yard, 10-minute drive to start the season. Unfortunately, his lone possession ended prematurely with a fumble and a concussion when linebacker Demario Davis put his helmet into McCown’s ear hole.

The intention of McCown’s dive toward the goal line was noble — sell out to score a touchdown on the first drive with his new team — but it changed the game. He was done for the day, if not longer, and his backup committed three turnovers in the second half.

Pettine doesn’t blame McCown, even after criticizing his reckless play in the preseason game against Tampa Bay.

“How do you tell him different?” he asked. “You’re talking about a guy, that was instinct for him to do that. Had the play occurred at the 10-yard line or midfield, more than likely — this is a question better for him — but probably would’ve slid. But you’re that close to the end zone.

“If he had hung onto the ball and gotten helicoptered in and landed and we had won the game, we’re carrying him off the field in a good way. So it’s easy in hindsight to say that because we know the end of the movie, but that would be real difficult to try to coach out of him, say, ‘Hey, listen, don’t risk yourself.’”

Davis supported McCown.

“If you can pick a guy who would dive there and who wouldn’t dive there, I think you’d pick the guy that competes and tries to get the ball in the end zone,” he said. “We put a lot of hours into trying to put the ball in the end zone, so when you get a chance to do it, you’re going to take it.

“But at the same time, you’ve got to understand the coach’s point of view and how valuable he is to this team. It’s just hard to say. It really is. If I was in that situation, I would’ve probably done the same thing.”

Davis wasn’t active Sunday, but the Browns almost needed a third quarterback against the Jets. Manziel scrambled seven times, including two that got called back by penalty, and was sacked three times. His 6-foot, 210-pound frame absorbed several blows, including a huge shot to the shoulder from cornerback Buster Skrine in the open field. Manziel’s helmet bounced off the turf, but he bounced right up.

Pettine said Manziel made it through the game OK.

“He did. I think a little sore, but nothing specific,” Pettine said. “Arm-wise he felt OK.”

Manziel’s first instinct is to bail out of the pocket and run.

“I think there were an instance or two where I thought he could have stuck with the read and I think part of it is that he saw a gain in front of him and went ahead and took it,” Pettine said. “There were a couple I thought it was textbook. He got positive yardage, he slid down and we were ready for the next play. And then there were the few — the one for sure that he took the real big hit on was unnecessary, especially in light of that Josh was already down for the game.”