CHICAGO — Michael Soroka will be on the shelf for at least the next two weeks.

But the fear is the newly acquired right-hander will be out for longer.

The Cubs officially placed Soroka on the 15-day IL Tuesday with a right shoulder strain and called up reliever Nate Pearson to add a healthy arm on the pitching staff.

Soroka — who turned 28 on Monday — had an inauspicious start to his Cubs career.

He struck out three batters in the first inning and gave up a solo homer in the second inning of Monday night’s loss.

But by the end of the second frame, his fastball velocity had dipped to 89 mph — down from his yearly average of 93.5 mph — and he came into the Cubs’ dugout to inform the team’s coaching and training staff.

Soroka said he felt his shoulder “grab” as he tried to put a little extra on a fastball, and the feeling didn’t go away.

Manager Craig Counsell confirmed after Monday’s game that Soroka would head to the IL, and the team made that official Tuesday afternoon.

“It’s never fun — it’s embarrassing. You come to this organization, and you hope to hit the ground running,” Soroka said. “Two innings later, we’re having to pull the plug.

“It’s concerning, but there is hope that it’s something that can be taken care of fairly quickly, and hopefully we’ll be back out there in some respect, at some point soon.”

It’s a brutal blow to Soroka and the Cubs, who gave up two Top 30 prospects to acquire the righty from the Washington Nationals ahead of the MLB trade deadline last week.

Soroka represented the top deadline acquisition after months of speculation that a big trade was coming to bolster the rotation. He was the only starter the Cubs acquired, joining relievers Andrew Kittredge and Taylor Rogers and utility player Willi Castro as the team’s complete deadline haul.

Soroka has a long history of injuries, dating to his time with the Atlanta Braves, when he tore his Achilles in both 2020 and 2021. He also missed time with a shoulder strain last year, and a biceps strain kept him sidelined for a month earlier this season.

The Cubs replaced Soroka in Monday’s game with Ben Brown, who might take the final rotation spot for at least a turn. The Cubs also have Jameson Taillon and Javier Assad currently on rehab assignments, though neither were expected to be ready to rejoin the big-league rotation in the next week.

Assad has made two rehab starts — including one last Wednesday — but he has missed the entire season while recovering from an oblique injury.

Taillon threw three innings in his first rehab start with Triple-A Iowa on Sunday and was roughed up for seven runs. He threw 64 pitches as he recovers from a calf injury, and in an ideal world, the Cubs would make sure he’s sharp before he rejoins the Chicago rotation.

They might not have that luxury anymore, however.

Brown has struggled in the rotation this season, with a 6.30 ERA and 1.52 WHIP in 15 starts. He has fared better (4.86 ERA, 1.08 WHIP) out of the bullpen.

When Taillon first landed on the IL in early July, the Cubs opted to use openers for several turns through the rotation, effectively going with bullpen games in the fifth spot.

This is Pearson’s third stint with the big-league club this season, including beginning the year in the bullpen. He carries a 12.66 ERA and 2.53 WHIP in nine games (10.2 innings). That includes his last appearance on June 22, when he surrendered five earned runs in two innings.

Pearson was a trade deadline acquisition last summer for the Cubs, and pitched well out of the bullpen with a 2.73 ERA and 0.99 WHIP in 19 games (26.1 innings). It looked to be that things finally might be clicking for the former first-round draft pick and top prospect, but he has not found the same success this year.