When the Cubs set their Opening Day roster on Thursday, Theo Epstein said he was confident veteran reliever Ryan Tepera would still pitch big innings for the club even though he wasn’t a part of the initial bullpen.

Before the first series of the season concluded, Tepera got the call to Chicago and will get an opportunity to become an important piece of the bullpen.

The Cubs placed left-handed pitcher Brad Wieck on the injured list Sunday morning with a right hamstring strain he suffered pitching in Saturday’s loss. Tepera was called on to replace Wieck, coming from the alternate site at South Bend.

Wieck gave up a 2-run shot to Christian Yelich in Saturday’s game and tweaked his hamstring on a pitch after that. The Cubs don’t yet know how long he will be shut down, but he will miss at least the next week-and-a-half.

Tepera, 32, spent the last five seasons pitching in the Blue Jays bullpen with a 3.64 ERA and 1.16 WHIP over 216 appearances.

Though he’s a right-hander, Tepera has had success against lefties throughout his career (.754 OPS) and that’s something manager David Ross has discussed with the veteran reliever as the Cubs are now down to only two left-handers in the bullpen.

“We’ve had that conversation. I told him before I sent him down — ‘I trust you’ and he’s proven, in my opinion, playing [in the AL East],” Ross said. “I haven’t played in every division, but that American League East is real with those ballparks and those lineups.

“He’s a guy that’s battle tested and you love his attitude and he continues to get locked in and sharpen.”

Due to some delays, Tepera was unable to get on the mound a couple times during the shortened summer camp and thus the Cubs wanted to give him more time to work up to speed.

“In his case, it’s not a matter of him not having the talent to help us,” Epstein said Thursday, “because we think he certainly does and is going to play a large role and help us. He was just a little bit delayed. There were a couple of instances in which he missed a sim game or a bullpen with procedural delays.

“So it put him behind a little bit and he was trending the right direction and certainly threw the best that he has all camp in [the exhibition game against the White Sox last Monday]. So we think he’s gonna pitch really big innings for us.”