An abashed smile stretched across the wide and stubbled face of Ravens rookie right tackle Roger Rosengarten as he slipped into a black T-shirt in front of his locker in Owings Mills on Wednesday afternoon.

“I got the rookie yips a little bit,” he told The Baltimore Sun. “Obviously you don’t want the first play to go like that, but I guess that’s a welcome-to-the-NFL moment against a really good player.”

The player, of course, was Chiefs defensive tackle and two-time All-Pro Chris Jones, and the play was the first of Baltimore’s third series in last week’s season-opening loss at Kansas City. Rotating in for starter Patrick Mekari in the hostile environs of a raucous Arrowhead Stadium with the score tied at 7 and the ball at the Ravens’ 20-yard-line, Rosengarten, the second-round draft pick out of Washington, had no shot.

Jones raced past him, as well as late-arriving right guard Daniel Faalele, and strip-sacked Lamar Jackson with a defensive alignment that was different than what Baltimore was expecting on the play, Rosengarten said.

Five plays later, the Chiefs scored the go-ahead touchdown and never relinquished the lead en route to a 27-20 victory.

“I got the rookie jitters out of the way the first week of the regular season in a really hostile environment,” Rosengarten acknowledged. “My biggest thing is just staying calm. I’ve been playing this game for a really long time and now you’re at the highest level of what you dreamed to be, so just staying calm through it. There’s a reason we’re all here.”As far as Ravens coach John Harbaugh is concerned, there are reasons, too, to be confident about the unit.

This, despite three new starters along a line in which Faalele is starting at right guard for the first time in his career, Andrew Vorhees is starting at left guard after being injured all of his rookie year last season, and Mekari and Rosengarten are sharing snaps at right tackle. Never mind that the line was flagged five times against Kansas City — four of them for illegal formation, including three on left tackle Ronnie Stanley, with the other a holding penalty on center Tyler Linderbaum that wiped out a long run by Jackson.

And things won’t get much easier this week, with Baltimore facing a Las Vegas Raiders defense anchored by elite edge rusher Maxx Crosby and star defensive tackle Christian Wilkins, who is coming off a career-high nine sacks (though injuries to defensive ends Malcolm Koonce and Tyree Wilson help).

“In regard to the penalties, the refs do what the refs are told to do,” Mekari, who was also flagged for illegal formation, told The Sun. “It’s frustrating that we had so many penalties. It was costly because it was such a close game.

“We definitely learned from it [and] don’t plan on it happening anymore. … Those refs were told something, they tried to enforce it that way and we got the short end of the stick.”

Nearby and nearly a week later, Stanley still steamed from the penalties as he began to get dressed at the end of the open locker room period.

Thursday night, he accused Shawn Hochuli’s officiating crew of “trying to make an example of me.” He also wondered aloud why the Chiefs’ tackles didn’t suffer the same fate, saying in Kansas City that he was lined up closer than their right tackle and that all the penalties made him “feel like I’m crazy, [that] I don’t know where I’m lining up.”

Penalties aside, other issues needed cleaning up, Mekari said, including better communication and finishing blocks.

Protection was also at times a problem.

The Chiefs pestered Jackson much of the night, though they had just one sack and one hit on the two-time NFL Most Valuable Player, who often escaped trouble with his legs, rushing for 122 yards. The Ravens’ offensive line was also ranked second in pass-blocking win-rate in Week 1, per ESPN.

Run blocking, however, was another story.

Running back Derrick Henry ran for just 46 yards on 13 carries, an average of 3.5 yards per attempt. Baltimore’s run blocking also ranked 22nd in win rate, per ESPN.

“Week 1 is tough,” Mekari said. “You don’t know what guys have been working on. But through the game you get more film, you get more tendencies, you get a better understanding of who [your opponents] are as a player, who you are as a player.

“It’s early in the year. There’s so much to grow from Week 1 to Week 2.”

And even with their struggles up front, the Ravens still had a chance to tie the Chiefs on the game’s final play, with Jackson scrambling and spinning in the pocket to avoid Jones. Mekari was supposed to fan out to block him, but couldn’t hear the call because of the crowd noise, Harbaugh said, and diminutive running back Justice Hill did an admirable job of slowing Jones down long enough for Jackson to find tight end Isaiah Likely, whose toe came down out of bounds in the back of the end zone to end the game.

“I’m not too worried about the offensive line,” Harbaugh said. “I watch all the other offensive lines in the National Football League, and I think if you applied some of the same standards to the other offensive lines out there, you’d be like, ‘Oh, boy, that’s a tough position to play against these guys.’ So, our offensive line is going to be really good this year. I believe that, and we’re working hard toward that.

“So, I’m not going to sit here and doubt those guys; I’m going to coach those guys, and those guys are going to get out there and play. I think by the end of the season, you’re going to feel really good about our offensive line.”