As of Sunday afternoon, Ben Rice said, he could still walk around New York with some anonymity.

The rookie first baseman, who was not a hot-shot prospect but one who gradually climbed the ranks after being drafted in the 12th round in 2021, debuted about three weeks ago, has hit well and on Saturday rewrote Yankees history books — those have been around a long time — in becoming the first rookie in franchise history to slug three home runs in one game.

The 25-year-old is 6-foot-1 and not an Aaron Judge or Giancarlo Stanton, whose hulking statures probably would be noticeable on the subway.

“I think I just blend in for the most part,” said Rice, whose most identifiable trait thus far has been a smile that has been pasted on his face.

With a profile that is rising, Rice was again atop the order for Sunday’s series finale against the Red Sox in The Bronx, which the Yankees lost, 3-0.

And for a 14th time Rice was starting at first base, a position he had not known until two years ago and a position he has played well enough to ensure his bat stays in the lineup.

The Massachusetts native grew up as a catcher and only caught at Dartmouth and during his first pro season. In 2022, though, a prospect with a strong bat and questionable glove began getting reps at first base — but not a ton.

In four minor league seasons, Rice started 114 games at catcher and just 52 at first base. He was still seeing time at both spots this season before Anthony Rizzo’s mid-June injury dictated that Rice’s first taste of the majors would come at first.

Manager Aaron Boone acknowledged he is “raw” at the spot. There have been growing pains, and there have been standout attributes.

“He moves well. He’s a good athlete,” infield coach Travis Chapman said. “Just working on different moves other than just receiving and throwing and … moving his feet around the base to be able to make more plays.”

Rice’s feet can help him make more plays than a traditional, more lumbering first baseman, but he is still mastering how far he can wander from the base while being able to scramble back in time to receive a throw.

On Saturday, Rice was unable to dig out a throw that Anthony Volpe had spiked, but generally he has made the plays he needs to.

There is not enough of a sample size for advanced metrics to be trusted, but the early signs were positive: Somehow, among all MLB first baseman, a player called up last month entered play rated 10th in Outs Above Average at the position.

“I think just adjusting to the speed of the game,” Rice said about the biggest challenge to learning the position on the fly. “Just trying to translate things in a practice setting to game-like situations.”

On Sunday, Rice was working around the base with Chapman a full hour before the rest of the Yankees’ infielders took ground balls.

He needs more reps, and Chapman has seen him get as many in practice as possible.

“Everybody thinks first base is easy — ‘Just go over there and go catch the ball,’ ” Chapman said. “The reality is you’re trying to get as many balls as you can, while getting to the base, using as much wingspan or creating as much wingspan as you can at first and helping your guys make as many plays as possible.

“He’s doing a nice job over there.”

At worst, Rice has been playable at the spot — and considering the slumping bats around him and his own performance at the plate, the Yankees will gladly keep running him out there.

On Saturday, Rice became the 26th player in Yankees regular-season history to blast three homers in a game, while his seven RBIs matched Lou Gehrig for the most by a Yankees rookie in franchise history, at least since the stat has been tracked in 1920.

A kid who grew up around Boston, with friends who are mainly Red Sox fans, finally checked his phone Saturday night.

“I was getting a good amount of notifications, to say the least,” Rice said.