Bryce Harper has gone nearly 400 innings without an error at first. Phillies manager Rob Thomson isn’t surprised.

Off the bat, it appeared to be a screaming line drive to right field. But it wasn’t hit as hard as it looked. So Bryce Harper timed his leap, then had to recalibrate while in midair.

No sweat, right? Well, maybe not for an experienced first baseman.

But Harper’s adjustment to first base for the Phillies, which began on the fly last season and has continued this year on a daily basis, couldn’t be going more smoothly. Entering Tuesday night against the Rockies, his 53rd start at the new position, he led all first basemen with three outs above average, according to Statcast.

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“As each day goes on, I’m less surprised, just because he looks so comfortable there,” manager Rob Thomson said. “Last year, I was surprised at the start of it because it’s tough. He’s never played there before. But he’s adapted really well, so I’m less surprised every day.”

Harper was drafted as a catcher and moved to the outfield in the minors. He spent the first decade of his major-league career primarily as a right fielder. But he volunteered to learn first base a year ago after Rhys Hoskins blew out his knee and began playing the position in games in July.

When the Phillies decided to stick with Harper at first base full-time, infield coach Bobby Dickerson predicted that he eventually could win a Gold Glove as an infielder.

Dickerson might end up being prophetic. Through Monday, Harper went 396 innings without making an error. He ranked second among first basemen with three defensive runs saved, trailing two-time Gold Glove winner Christian Walker of the Diamondbacks.

Harper’s latest gem — the leaping catch against the Rockies’ Elehuris Montero — came in the 10th inning Monday night. It kept the go-ahead run from scoring and helped enable the Phillies eke out a 2-1 victory.

“It was kind of one of those weird ones,” second baseman Bryson Stott said. “He goes up, and it’s not hit too hard, so you’re kind of timing your jump differently. He got up there to snag that one. It was a huge play.”

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Harper was still trying to find his timing at the plate. Apart from a three-homer game April 2 against the Reds, he hadn’t gone deep and had only three extra-base hits (all doubles) through Monday night and was in a 3-for-30 funk.

A potential positive sign: He scorched two balls Monday night, an RBI single at 107.8 mph and a flyout to center field at 104.5 mph.

“The name of the game is getting hits,” Harper said last week. “I’m just trying to go up there, get the hits, and have good at-bats. Obviously, you guys know if I’m swinging at pitches out of the zone, I’m going to get out. I’ve just got to stay the course and just have better at-bats each day.”

Even before they faced the Rockies’ Austin Gomber on Tuesday night, the Phillies had 245 plate appearances against left-handed pitchers, third-most in baseball.

It has created opportunities for lefty-swinging Brandon Marsh to face lefties.

Marsh started for the fourth time in eight games against a lefty starter, with Thomson explaining that Gomber isn’t necessarily tougher on lefties than righties. Marsh is 3-for-14 with a double and seven strikeouts against lefties.

“I think he’s staying on the ball a little bit more, and his focus is more to left-center,” Thomson said. “He’s got to do that. That’s what lefties have got to do on lefties because they’re always going to spin the ball away from you. I think he’s doing a better job of that.”

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Johan Rojas took his familiar spot in center field, which was notable only because he appeared to be injured amid the Phillies’ on-field celebration after Monday night’s victory.

“He got stepped on,” Thomson said. “But he’s fine.”

Rojas said as much before leaving the clubhouse Monday night. He had a brief conversation with a trainer but didn’t appear to require treatment.

“I think it scared him more than anything,” Thomson said.

Right-hander Taijuan Walker (shoulder) allowed one run on three hits and three walks in 4⅔ innings for triple-A Lehigh Valley. His fastball touched 92 mph in the first inning. It was the second start in what likely will be a three- or four-start minor-league assignment before he joins the Phillies’ rotation. ... Cristian Pache’s game-winning single in the 10th inning Monday night was the first walk-off hit of his career. It also came in only his fourth at-bat since April 7. He entered the game in the ninth inning as a pinch runner. … MLB commissioner Rob Manfred met with the Phillies before the game. Manfred routinely visits each team early in the season. … Cristopher Sánchez (0-2, 3.52 ERA) is scheduled to face Rockies righty Ryan Feltner (1-1, 3.38) in the series finale at 6:05 p.m. Wednesday on NBC Sports Philadelphia and 94-WIP.