CHICAGO -- Nico Hoerner sat down in the outfield grass on Sunday in Cincinnati, dealing with not only the physical toll of his collision with Ian Happ, but also the overwhelming concern for his friend and teammate.

On Tuesday morning, Hoerner was counting their combined blessings in a Zoom discussion with reporters, given that soreness was the main outcome of the alarming play. Hoerner was placed on the 10-day injured list with a left forearm strain, while Happ was dealing with a rib contusion, but no concussion symptoms.

"All things considered, we're both pretty fortunate," Hoerner said. "I was honestly pretty stressed in the outfield, just not knowing what condition he was in. Pretty shaken up, just seeing a friend leave the field like that. That doesn't feel good at all.

"So when I could go back to the locker room and I could see him, and he was in good spirits and stuff, that definitely made me feel good. Because that was probably the scariest baseball play I've been a part of. I'm glad he's in a good spot. He's going to be just fine -- we both are."

In the eighth inning of Sunday's 10-inning, 13-12 loss to the Reds, Hoerner was playing second base and was running in pursuit of a Tyler Stephenson flare to shallow center. Hoerner made the catch, but collided hard with Happ in the process.

Happ was hit in the head on the play and kicked in the ribs as Hoerner fell to the ground. The center fielder went through MLB's concussion protocols and came through fine, per manager David Ross. On Tuesday morning, Happ planned on going through more testing, including taking light swings.

"He is kind of day to day," Ross said. "Tests seem to be all good. He's pretty sore in a lot of different areas. He ran through a ton of tests."

Hoerner -- batting .389 with six doubles and a 1.056 OPS through 11 games -- expressed optimism that he would not need more than the allotted 10 days on the IL. That would put him on target for activation for the Cubs' weekend set against the Tigers, beginning May 14.

"I personally very much expect to be back playing against Detroit," Hoerner said. "I think it's a mid-season chance to really, fully get my body under me in all ways. And I'm going to take advantage of that as best I can."

Arrieta placed on IL
The Cubs also placed veteran starter Jake Arrieta on the 10-day IL on Tuesday with a right thumb abrasion. The issue flared ahead of Arrieta's outing on Friday, when he allowed seven runs in 3 1/3 innings in Cincinnati.

The cut on Arrieta's pitching thumb hindered his ability to throw his cutter, and the issue was still present during a bullpen session on Monday at Wrigley Field. With three off-days looming (Thursday, Monday and May 13), the Cubs felt it was best to let the righty rest and recover.

"It's just affecting one of his main pitches," Ross said. "It's just not something that we feel comfortable pushing on. And again, with that and the off-days coming up, just him missing a start makes a lot of sense to get that thing healthy, so it's not something that either continues to linger or worsens as he continues to pitch."

Winkler also shelved
Reliever Dan Winkler was also placed on the 10-day IL due to right triceps tendinitis, which has been present "for a little while," according to Ross. Similar to Arrieta, the Cubs felt the looming off-days presented a chance to let Winkler rest without missing too many games.

Winkler has logged a 0.84 ERA with 12 strikeouts through 13 relief appearances this season as a setup man.

"It's been something that he's just been kind of pitching through," Ross said. "And I think, when you've got tendinitis, the back-to-backs are just tougher. He's thrown the ball really well for us."

Worth noting
? Lefty Kyle Ryan and righty Keegan Thompson were recalled from Triple-A Iowa to take the active roster spots vacated by Arrieta and Winkler. Thompson was slated to make his first career start in Game 2 of Tuesday's doubleheader against the Dodgers.

? Righty Adbert Alzolay was originally scheduled to start on Tuesday night, but he will shift to Wednesday's game against Los Angeles. That was originally Arrieta's day to pitch.

? Utility man Ildemaro Vargas had his contract selected from Iowa to replace Hoerner on the active roster. Vargas got the start at second base in the Cubs' 7-1 Game 1 win on Tuesday, going 1-for-3 with a run scored.

? Right-hander Kohl Stewart was recalled from Iowa between Game 1 and Game 2 on Tuesday to serve as the 27th man on the active roster.

Quotable
"I was able to stay pretty present, I guess. But yeah, it was a pretty wild game. That game felt like an entire series just in itself, honestly. It was a great baseball game. It was a lot of fun to be a part of. Both physically and the result, not what you want to get out of it. But those are games you love to be a part of and impact and get to experience." -- Hoerner, on staying in Sunday's loss after his collision with Happ