The Orioles finished their first three-game sweep of the season Sunday with a 4-0 shutout of the Chicago White Sox, and a returning veteran was right in the middle of it.

Chris Tillman came off the disabled list to make his 2017 debut after right shoulder bursitis sidelined him since spring. It was his first major league appearance since the Wild Card Game in Toronto that ended the Orioles’ season in 2016.

“It’s been long. I’m going to tip my hat to [trainers] Richie [Bancells] and Brian [Ebel],” Tillman said. “They did a heck of a job, and it feels good to finally go out there and pitch again.”

Tillman’s rehab performance didn’t exactly inspire confidence that he was ready to face major league hitters. He was 0-3 with a 7.16 ERA and seven home runs allowed in his five starts across various minor league levels.

Tillman’s last rehab start before he faced the White Sox on Sunday was against their Triple-A affiliate, the Charlotte Knights. Tillman coughed up four home runs in that outing.

So Orioles fans could be forgiven if they feared Tillman may have been rushing back too soon, as closer Zach Britton did before returning to the 10-day DL on Saturday. And Tillman didn’t ease those worries when he walked the first White Sox batter he faced, Melky Cabrera, on four pitches. In fact, his first seven pitches were all out of the strike zone — mostly missing outside — as he issued consecutive walks to start the game.

“The first seven pitches were all the same mistake,” Tillman said. “It was kind of an easy adjustment, because I wasn’t all over the place, I just kept making the same mistake over and over and throwing the ball outside. So I think it was just a small minor adjustment to get back over the plate and make quality pitches.”

Tillman got more comfortable as the game went on. He escaped a bases-loaded jam to get out of the first inning unscathed, and he didn’t allow another runner into scoring position until the fourth, a rally he defused on a Cabrera groundout.

“The first inning there, it felt like I’d never thrown a pitch in the big leagues before, but that’s just kind of normal,” Tillman said. “When I got through that and made some good pitches to get out of it, I think I felt pretty good with where we were at.”

By the end of his scoreless five-inning stint, the veteran righty looked like vintage Tillman. His fastball hovered around 89-90 mph — a tick off his average 2016 velocity of 91 mph — but he found the strike zone and rattled off a few good breaking balls to keep hitters off balance. Tillman exited with his pitch count at 93, and a line that included three hits, three walks and four strikeouts.

“It was a real testament to his pitchability, searching for something he could survive with early, where he could get in step a little bit,” manager Buck Showalter said. “Chris has got a lot of weapons. I remember when we first had him, it was really a two and a half pitch mix. Now it’s the cutter-slash-slider, he went to that some later on. Changeup, he found a feel for that. He’ll tell you I don’t think he really felt good about the command of his fastball most of the outing, but he and [catcher Francisco Pena] found a way to survive.”

If Tillman’s outing was a sign of what’s to come, he provides an instant upgrade to the Baltimore rotation. Granted, the Orioles were able to hold the staff together during Tillman’s absence. They needed a fifth starter only three times, and in each case, they received a quality start (two from Alec Asher and one from Jayson Aquino). But that wasn’t a long-term solution.

The Orioles need their longtime ace to provide stability atop the rotation, and Tillman took the first step toward doing that on Sunday. And now Asher, Aquino, Gabriel Ynoa and others are available as rotation depth in case the struggling Ubaldo Jimenez doesn’t improve.

“Hopefully, today was a good step for us,” Showalter said. “Nice to have him back.”

The injury report

Jonathan Schoop, after starting 190 consecutive games from 2015-2017, missed his second consecutive game Sunday with swelling in his right hand. The Orioles are optimistic he’ll be ready to return soon, and they’d likely wait a couple more days before determining if a DL move is necessary.

Meanwhile, the Orioles added to their list of walking wounded when Pena, making his first start of the season, had to leave the game with cramping in his thumb during eighth-inning warmups. Pena had been playing well, calling a shutout behind the plate and getting two hits in the game.

“Just cramped up,” Showalter said. “I thought he’d taken a ball off the thumb or something. I’ve never seen that. Richie said he’s seen it before. He was cramping, really most of his body, but really down his thumb and his forearm. … Richie thinks it usually manages over 24 hours, but we’ll see.”

The Orioles are already down one catcher, with Welington Castillo sidelined with right shoulder tendinitis. Pena replaced Castillo on the roster, but if Pena too has to miss time, the club’s catching depth will be further tested.

If Pena ultimately is DL’d, don’t bet on the Orioles calling up top prospect Chance Sisco. Sisco has struggled for Norfolk this season, hitting just .236 with a .646 OPS and no homers in 21 games. Additionally, early reports on his defense haven’t been great. He’s thrown out 23 percent of attempted basestealers. The Orioles likely want to keep him in the minors as he continues to develop.

Other catching options in the minors include Norfolk backup Armando Araiza — whom the Orioles just acquired from Atlanta on Thursday — and Double-A Bowie catchers Yermin Mercedes and Austin Wynns. Again, none is on the 40-man.