Seranthony Domínguez has given up two homers with his slider. The Phillies say they aren’t concerned.

ST. LOUIS — Coming into the season, Seranthony Domínguez had thrown 854 sliders in the majors and allowed a total of three home runs. It’s notable, then, that he has given up two homers on 25 sliders so far this year.

Chalk it up to small-sample randomness, according to the Phillies.

“Obviously he’s given up a little bit of damage, but for me, the last week-and-a-half is probably the best command of the pitch, command of the shape, that I’ve seen in a long time,” pitching coach Caleb Cotham said Tuesday. “I’m really actually excited how he’s throwing, in general, but definitely his slider.”

» READ MORE: A struggling Johan Rojas says he’s been ‘a little shy’ at the plate. He broke out against the Cardinals.

Domínguez inherited a 2-0 lead from starter Spencer Turnbull in the seventh inning Monday night and hung a slider in a 1-1 count. Cardinals catcher Iván Herrera hit it off leaping left fielder Brandon Marsh’s glove and into the Phillies’ bullpen for a solo homer.

In the second game of the season, Domínguez gave up a three-run shot to the Braves’ Marcell Ozuna on a similarly mislocated 1-1 slider.

“[Monday] night, the one he leaves over the middle gets hit out, but his last three or four outings are probably the most consistent run of sliders he’s had,” Cotham said. “His best, his nastiest ones emerge from that. He’s put a lot of work into that.”

Manager Rob Thomson concurred with Cotham, lauding Domínguez for his aggressiveness early in counts and noting that the slider “looks good.”

Last season, Domínguez gave up fewer hits (nine) but also got fewer swings-and-misses (46.6%) than in 2022 (11 hits, 57.1%). Cotham said Domínguez worked in spring training to be more consistent with the shape and location of the slider, which he typically throws more than 25% of the time.

“It’s a pitch that he’s struggled with in the past, but it’s very consistent and he feels good with his delivery,” Cotham said. “When he’s there, he can let it rip. I’ll bet on him throwing a really good slider in the strike zone all day, every day. We don’t believe [those homers] are going to happen very often right there.”

» READ MORE: Phillies’ Nick Castellanos finally ‘at peace’ with playing in the Philadelphia sports fishbowl

More fun with small samples: Nick Castellanos is swinging at fewer pitches out of the strike zone (34.4% entering play Tuesday night) than he did last year (career-high 41%), just as the Phillies hoped.

But he was also 4-for-35 without an extra-base hit.

Johan Rojas suggested after a three-hit game Monday night that he’d been “a little shy” at the plate in an attempt to be more selective. Is it possible that Castellanos is going through a similar adjustment?

“Absolutely,” Thomson said. “There could be a couple of guys going through that, to tell you the truth. I think we have to be careful sometimes because we talk about, ‘Don’t chase, don’t chase, don’t chase.’ But you have to have balance there because you want to maintain your aggressive in the strike zone.”

After tossing six scoreless innings Monday night, Spencer Turnbull became the fourth Phillies pitcher — and the second in 111 years — to not allow a run in either of his first two starts for the club.

Not bad considering he wasn’t even in the starting rotation until Taijuan Walker injured his pitching shoulder at the end of spring training.

Turnbull’s success can be tied to the development of a sweeper, the trendy slider variant that has become common across the sport. He toyed with a sweeper last season but started to throw it more seriously in spring training after signing with the Phillies.

» READ MORE: Spencer Turnbull gives Phillies six scoreless innings in 10-inning victory over Cardinals

Bryce Harper wore a ski mask last Tuesday night when he bashed three homers in a game against the Reds. Given that he hadn’t gone deep since, he broke out the headwear again Monday night, even though it was 76 degrees at first pitch.

Did Harper get any strange looks in the dugout?

“I thought it was just sort of like a rabbit’s foot or something,” Thomson said.

And baseball players — Harper, in particular — are notoriously superstitious.

Orion Kerkering pitched a scoreless inning Tuesday night in triple A, topping out at 99 mph, according to Statcast. The young reliever is scheduled to pitch for Lehigh Valley again Thursday before likely joining the Phillies’ bullpen Saturday. Kerkering missed a week of spring training after coming down with the flu. ... Lefty Bailey Falter is lined up to start Friday night for the Pirates at Citizens Bank Park. The Phillies sent Falter to Pittsburgh at the trade deadline last year for triple-A infielder Rodolfo Castro. ... Aaron Nola (1-1, 5.40 ERA) is scheduled to start the matinee series finale at 1:15 p.m. Wednesday against Cardinals righty Lance Lynn (0-0, 4.15).