Entering this season, the Cubs felt like their rotation depth was in a healthy position.

It’s being put to the test early in the season.

The Cubs placed righty Jameson Taillon on the 15-day injured list with a left groin strain. Righty Javier Assad took his place on the roster and started the Cubs’ series opener against the Dodgers at Wrigley Field.

“Just not really much to explain other than just felt a little something in the groin and didn’t feel like that’s something we should push,” manager David Ross said. “It was pretty sore. Got some work on [it] loosened up a little bit but then some time went by, and it tightened back up. Hopefully it’s minimal stay on the IL.”

I’m going to put my head down and attack this rehab/recovery! I’ll be doing every single thing in my power to come back stronger, and in good time. Can’t wait to get back to competing, and getting after it with the boys all summer long at Wrigley!! 💪😎

— Jameson Taillon (@JTaillon50) April 20, 2023

Taillon felt the injury on Wednesday playing catch in Oakland. Last season, the news would have been a tough blow to the Cubs, but this year, they feel they’re better pace.

“I think last year we didn’t have enough depth to withstand,” president of baseball operations Jed Hoyer said. “Hopefully this year, we have guys like Javi.”

Assad turned in a respectable performance considering he isn’t fully stretched out after starting the year in the Cubs’ bullpen and only received word yesterday about the start. He allowed 2 runs on 3 hits with 3 strikeouts in 3 innings of work while throwing 62 pitches.

Beyond Assad, though, the Cubs might have an established, veteran started returning soon.

Kyle Hendricks was scheduled to throw a bullpen in Arizona on Thursday and will throw 3 innings in an extended Spring Training game on Saturday for the Cubs. The hope would be for Hendricks to progress to 4 innings and roughly 60 pitches in his next outing, provided Saturday’s goes well.

“I think at this point it’s just really a matter of just getting innings under his belt, building up,” Hoyer said.

The Cubs played it slow with Hendricks return — partly to allow his capsular tear to fully heal and partly to work in a velocity program to add some zip back to his pitches.

“I think when he was winning ERA titles and those things, he was touching 90 [mph] and that had come down a little bit,” Hoyer said. “I think that he’s not [Oakland’s top prospect] Mason Miller throwing 102 miles an hour, but when he throws 88-90 [mph], his changeup is that much more effective. He put in a lot of time and worked on his velocity and focused on that. I think the hard work is paying off.”