MESA, Ariz. — As the Cubs worked this offseason to accumulate arms, they did so with the knowledge that injuries occur and can cause the need for that depth.

They found that out on the second day of spring training.

Manager Craig Counsell announced on Monday that a pair of young pitchers — Javier Assad and Brandon Birdsell — are dealing with injuries and are shut down as camp ramps up.

“Javier Assad is having some oblique soreness, so he’s out right now,” Counsell said at Sloan Park. “Brandon Birdsell has some — [we’re] trying to identify [exactly what] — it’s some back, back of the shoulder, lat [issue] and we’re trying to get to the bottom of that as well.”

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Assad arrived in Arizona healthy and experienced the injury on the team’s watch, pitching coach Tommy Hottovy said.

“He had thrown a bullpen, it felt good, did a workout afterward and it was just something that kind of just came up after,” Hottovy said. “It wasn’t anything like an acute throw injury type of thing. It was more of just something that kind of came up after the fact.”

It’s too early to determine the extent of the injury — Counsell said Assad was scheduled to have imaging done later Monday to determine the severity.

“Then you’ll want an answer tomorrow and we’ll play that game,” Counsell quipped.

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The righty figured to be in the Cubs’ rotation mix to start the season after posting a 3.73 ERA in 29 starts (147 innings) last year. In 294 big-league innings, Assad has a 3.40 ERA and has shown the ability to be a dependable pitching piece, even if he isn’t the flashiest pitcher.

The Cubs added lefty Matthew Boyd and righty Colin Rea this offseason via free agency to bolster their rotation depth in case this type of exact situation arises.

“At this time of year, you always feel pretty good, right? There’s a lot of numbers, right?” Counsell said. “You hope that maybe your depth is a little better. I think we are in a better place from that perspective.

“And then it’s about keeping guys healthy. But I think from a depth perspective, we are in a pretty good spot right now.”

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Birdsell figured to be one of those depth options.

The prospect is a non-roster invitee and was the team’s minor-league pitcher of the year in 2024 after posting a 3.91 ERA across 135.2 innings with 134 strikeouts in 27 games with Double-A Tennessee and Triple-A Iowa.

He wasn’t a pitcher who was going to make the team’s Opening Day roster, but there was still value in having him in camp.

“The goal for guys like a guy like Brandon Birdsell — who we know what he could do for the future of this organization — is to get him in camp and get him around players and just get to know what the workload looks like and what the routine looks like,” Hottovy said. “And so even though he’s going to be down for a little bit, it’s not going to stop what I think he’s going to be able to accomplish being around the guys.

“And again, our ultimate goal with guys like him is to get him ready for a healthy season, not rush for Opening Day.”