CHICAGO -- Lucas Giolito is feeling significantly better each day, but the White Sox ace was still placed on the 10-day injured list Tuesday (retroactive to April 9) with an abdominal strain. Giolito was joined by outfielder AJ Pollock, who was placed on the 10-day IL (retroactive to April 10) with a strained right hamstring.

Giolito made his third straight Opening Day start Friday in Detroit but left after four scoreless innings and 61 pitches when he felt tightness on three straight pitches. A trip to the IL was a foregone conclusion, with the right-hander hoping to miss no more than two starts.

“It's still early in this process,” White Sox general manager Rick Hahn said. “We all remain cautiously optimistic that he'll miss two starts. He's progressing nicely.

“Quite frankly, at this point, it's probably a little bit more about reining him back and keeping him on a prudent ramp back up, realizing that we want him strong for the next six, seven months here, not just for next week in Cleveland, let's say. But right now, everything's progressing in a positive way and we can stick with that two-start estimate.”

Jimmy Lambert, Chicago's No. 16 prospect per MLB Pipeline, will take Giolito’s next starting slot, having been recalled from Triple-A Charlotte. Lambert’s innings aren’t built up at this point, so he’ll be more of an opener for the White Sox.

Tuesday marked the first time Giolito was able to go outside and play catch.

“Recovery and rehab and all that has been going about as good as possible,” Giolito said. “It’s still early. It’s a nice ramp up to get back out there. I’m very confident I’m not going to feel anything. I’ve been throwing a baseball weight plyo ball against the wall last couple of days, and that’s felt completely fine.

“It’s a matter of letting it heal, doing the right kind of exercises and ramping up. I looked at it over and over and I think it was just one of those random things that can happen. As far as an adjustment mechanically that needs to be made, I don’t think it’s really something that needs to be pursued too hard. It’s just kind of one of those weird things. It’s unfortunate.”

A frustrating part for Giolito is that he worked all offseason and Spring Training to get ready for this season, preparing for a healthy 2022. And then he got injured in his first game.

“Best way to describe it is extremely frustrating, but with each day that’s passed, I’ve felt better and better,” Giolito said. “I really don’t think that it’s a big deal. [I'm] channeling that initial frustration into determination into putting the work in and getting back out there when I can.”

Pollock, meanwhile, is in Arizona with his wife for the birth of their second child. He left in the first inning of Saturday’s 5-2 victory over the Tigers, and with the outfielder already heading to the paternity list, the White Sox weren’t sure how he would feel exactly and erred on the side of caution.

“We are optimistic come Day 11 or 12, he should be ready to get going again,” Hahn said. “We aren’t going to know for sure until he gets back [from the paternity list] on Day 6.”

Left-handed reliever Anderson Severino, Chicago's No. 20 prospect, was recalled from Charlotte along with Lambert, meaning the White Sox have 15 pitches on their 28-man April roster.

“[Executive vice president] Kenny [Williams] and I were joking about this a couple of days ago,” Hann said. “We used to argue about 11 vs. 12 pitchers on the staff. Today, your beloved White Sox have 15.

“It’s part of what we are dealing with early this season in this unique year. Anderson is going to get an opportunity at some point to show not only that he can help us get outs but that he belongs once we stabilize a little bit and get into a more normal-sized pitching staff.”