No longer an unknown commodity, the Phillies are ready to unleash reliever Orion Kerkering

Orion Kerkering appeared in seven of the Phillies’ 13 playoff games last October because he has some of the nastiest stuff in the bullpen. But it also helped that he was a mystery.

Not anymore.

After shooting through four levels of the farm system, making his major-league debut near the tail end of the season, and then pitching on the postseason stage, Kerkering is a known commodity now. There weren’t any surprises, then, when he made his first appearance of the season Sunday against the Pirates.

And that’s what will make Kerkering so fascinating to watch.

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The Phillies believe Kerkering has the ability — and just as importantly, the head — to succeed as a leverage late-inning reliever, perhaps even eventually as a closer if manager Rob Thomson elects to designate one. But he also will face teams that have more detailed scouting reports on him and hitters with better plans for handling, say, his signature slider.

“I think it’s super exciting just cause I love a challenge,” Kerkering said Monday before the opener of a three-game series with the Colorado Rockies at Citizens Bank Park. “Whether I do fail and I can learn from it, or do succeed and keep rolling with it, that’s what drives me more. Because I know this is the hardest game between all the levels. Being here is a dream, but now it’s also your job to compete every day and stay here for a long time.”

There are always reminders. Kerkering opened the season on the injured list after missing a week in spring training with the flu. He returned Sunday, entered with the Phillies trailing, 6-2, in the seventh inning, and promptly struck out the Pirates’ Bryan Reynolds on a slider.

But he also struggled to command his fastball, walking Ke’Bryan Hayes on four pitches before recording two outs with the slider again.

“I think I was just rushing myself, honestly,” Kerkering said. “That’s why the slider was called so much. Just first-day excitement to be out there again. That was probably the cause of the four-pitch walk. Just lost some concentration. But honestly, I’m ready to throw anything.”

The Phillies are ready to unleash Kerkering, too. He will move into the late-inning mix, giving them another right-handed option alongside Jeff Hoffman and Seranthony Domínguez, who continues to give up homers on his slider despite receiving praise from Thomson and pitching coach Caleb Cotham for how well he’s throwing it.

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Kerkering didn’t appear in back-to-back games last season until the National League Championship Series against the Diamondbacks. He hasn’t done it yet this year, either, and probably won’t right away, according to Thomson.

That’ll be another challenge.

“I feel like I can do it,” Kerkering said. “But I know the season’s not one month. It’s six months — and then including October and November. Just being able to understand that and just know they’re trying to look out for you for the long road. I want to throw every day, but it’s better to pitch in October than it is in April.”

Whit Merrifield made his seventh start in 17 games in place of resting third baseman Alec Bohm, another opportunity for the slow-starting utility man to get going at the plate.

Merrifield was 3-for-25 and had not yet hit a ball harder than 95 mph.

For much of his career, Merrifield has been an everyday player. That isn’t the role with the Phillies, who didn’t guarantee at-bats to the 35-year-old when they signed him for $8 million in February. Barring injuries, Merrifield is likeliest to fill in at multiple positions.

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“I think it’s taken its toll on the quality of his at-bats, not playing every day,” Thomson said. “But he’ll get it going. He’s getting used to the role, basically. It’s a process. You’ve got to prepare a little bit differently. I think he’ll get used to it.”

The Rockies’ visit is a homecoming for outfielder Nolan Jones, who grew up in Bucks County, graduated from Holy Ghost Prep in 2016, and was playing at Citizens Bank Park for the first time as a major leaguer.

Jones, 25, made his major-league debut with the Guardians in July 2022 and got called up by the Rockies last May, one month after they came to Philadelphia. He had a breakout season last year, batting .297/.389/.542 with 20 homers and 20 steals.

Taijuan Walker is scheduled to throw five innings (or 80 pitches) Tuesday night for triple-A Lehigh Valley, the second start in his recovery from a right shoulder impingement. His fastball averaged 91 mph last week for low-A Clearwater. … Reliever Luis Ortiz (ankle) is lined up to throw live batting practice Tuesday in Clearwater, Fla. … Ranger Suárez (2-0, 2.65 ERA) will face Rockies left-hander Austin Gomber (0-0, 4.91) at 6:40 p.m. Tuesday on NBC Sports Philadelphia+ and 94-WIP.