ANAHEIM, Calif. — Didi Gregorius went 4-for-4 Monday night, upping his average to .344.

If he was eligible, Gregorius, who missed the first month of the season and therefore doesn’t have the requisite minimum of at-bats, would rank second in the AL in batting average (behind Aaron Judge’s .347).

And almost no one has noticed.

“Didi in this lineup has really been overshadowed,” Joe Girardi said.

No surprise there, of course. Judge has done that to just about everyone on the roster.

“He doesn’t mind flying under the radar,” Girardi said of Gregorius.

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The 27-year-old Gregorius, who continues to play terrific defense, is slashing .344/.367/.513 with six homers and 25 RBI in 40 games. He brought a 14-game hitting streak into Tuesday, hitting .397 with three homers, four doubles and three homers in the stretch.

All of it after hitting a career-best 20 homers in 2016.

It has been nothing but growth from his horrendous first month, in April 2015, when he took over for a certain retired icon at shortstop.

“I think for Didi, he came in in a tough spot,” Girardi said. “He wasn’t really replacing Derek [Jeter], Derek had retired, but still the memories of Derek will never fade here and there are high expectations at the position.”

Chapman eyes Sunday return

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LHP Aroldis Chapman (rotator cuff inflammation) had his rehab outing with High-A Tampa rained out Tuesday, so he’ll pitch Wednesday, Girardi said, followed by an outing Friday. After that, it’s expected the closer will travel to the West Coast Saturday and be activated Sunday in Oakland, Girardi said. Dellin Betances has six saves in Chapman’s place and has allowed one earned run in 22 appearances this season.

Extra bases

Girardi said RHP Masahiro Tanaka, who pitched well Monday, will start on regular rest Saturday in Oakland . . . RHP Chad Green, who spot-started in place of Tanaka Sunday and threw 53 pitches over two innings, should be available out of the bullpen Thursday when the Yankees start their four-game series against the A’s.