OAKLAND, Calif. — Mark Teixeira’s description of his performance this season was far harsher than managing general partner Hal Steinbrenner’s.

“I’ve been terrible the last month,” Teixeira said Wednesday. “I just have to get it going, especially lefthanded.”

Teixeira was one of four Yankees whom Steinbrenner mentioned Wednesday afternoon — “called out’’ would be a tad strong for what the owner actually said — as playing significant roles in his club’s slow start.

“I don’t blame him,” Teixeira said. “Righthanded, my swing feels a lot better. I’ve been facing a lot of lefties and I feel like I’ve got that pretty locked in right now, but lefthanded, I’ve been pretty bad.”

Teixeira went 0-for-5 with three strikeouts Wednesday night against Arizona and was not in the starting lineup Thursday night against the A’s. He entered the night with striking splits: a .306/.404/.388slash line as a righthanded hitter (not including three at-bats in which he batted righthanded against a righthander) and a .148/.258/.259 slash line while batting lefthanded.

Teixeira, 36, has always been better as a righthanded hitter — a career .291/.385/.519 slash line from that side compared to .262/.353/.512 as a lefthanded hitter — but nothing like this.

He hit three homers, all while batting lefthanded, in his first 25 at-bats this season but entered Thursday night with a homerless streak of 108 at-bats in 30 games since hitting one against the Blue Jays’ Drew Storen on April 13. He had a .194/.298/.231 slash line in that span.

Teixeira has never been a player who has tried to hit home runs, but he somewhat wearily joked, “Maybe I should start.”

He added, “I’ve always been a guy that really just tries to square the ball up and my natural swing puts the ball in the air and the home runs come. Hopefully they will start coming . . . I’m just not driving the ball lefthanded. Just off enough. All it takes is to be off a little bit and too many ground balls. Something I’m trying to work on.”

The first baseman, whose slump has not extended to the field, said part of what’s been most vexing is how he’s felt while putting the work in.

“That’s the thing that’s a little frustrating, is in the cage and in batting practice, everything’s fine,” Teixeira said. “But you face some tough pitchers and you expand the zone a little bit and I’m not taking my walks like I was earlier. I need to swing at better pitches and hopefully the home runs will come and I’ll draw my walks when I need to and then hopefully get on a roll.”

Teixeira has said that seeing so many lefthanded starters this season isn’t an excuse for his troubles, but Joe Girardi isn’t so sure.

“It seemed like he was in a good spot when we left spring training, he was hitting the ball well, and then all of a sudden, we faced a bunch of lefthanders and he kind of lost it,” Girardi said. “He’ll find it. I don’t think he’s that far off. I’m going to bet on him that he gets it going.”

Teixeira said it did sting to be mentioned by the owner as one of the reasons the Yankees are not playing better.

“I’ve been around long enough to know that you’re going to get singled out when you’re not producing, especially with the type of career I’ve had,” he said. “I’ve always been someone that’s been able to carry teams during tough streaks, and we’ve been in a tough stretch the whole season, and I’m the kind of player that can carry a team for a while. I just haven’t done it yet.”