Yankees manager Joe Girardi must have figured something was up when he walked into his office after New York finished off the Baltimore Orioles.

There was general manager Brian Cashman, ready to talk — and not about Bobby Abreu’s two home runs or another strong start from Joba Chamberlain.

The Yankees shored up the catcher spot by acquiring 14-time All-Star Ivan Rodriguez from the Detroit Tigers yesterday, a deal that went down just as Abreu was hitting the second of his two homers to go along with one by Alex Rodriguez in a 13-3 rout of the Orioles.

“Guys like Pudge don’t come around every day,” Girardi said. “He’s the complete player.”

Jorge Posada had season-ending shoulder surgery yesterday, and while defensive whiz Jose Molina has been solid behind the plate, the 36-year-old Rodriguez still represents a significant upgrade. He was hitting .295 with five homers in 82 games this season, and has 13 Gold Gloves to his credit.

New York gave up reliever Kyle Farnsworth to get him, a move made possible with the acquisition of reliever Damaso Marte along with outfielder Xavier Nady from Pittsburgh last Friday.

“He’s hopefully going to be an important part of what we’re trying to do this year,” said A-Rod, who was teammates with Rodriguez from 2001-02 with the Texas Rangers.

Cashman said the deal was finalized during the seventh inning of the game against Baltimore, which helped New York avoid its first three game sweep by the Orioles at Yankee Stadium since 1986.

Abreu did most of the damage in a rare start at DH, adding a double to his two homers while giving the Yankees a big boost as they head into a four-game series with the Los Angeles Angels. Forty-one of New York’s last 55 games are against teams at or above .500.

“I don’t really like too much the DH. It’s one of the ways to get a day off,” Abreu said, smiling. “I had a good day, but I don’t like the DH.”

Mixing an improving slider with an overpowering fastball, Joba Chamberlain retired 11 of the final 12 batters he faced to win consecutive starts for the first time in his young career. He gave up two runs — only one earned — and five hits in six innings, striking out six without a walk.

Chamberlain (4-3) has allowed only two earned runs over his last three starts covering 19 innings.

“They were aggressive early on the fastball,” Chamberlain said. “When Jose recognizes that and our offense scores runs, it’s pretty easy.”

Taking the ball in place of Brian Burres just a short drive from where he grew up, Baltimore right-hander Dennis Sarfate struggled with control and got little help from his defense in his first big league start.

By the time Sarfate (4-2) left after four innings, the career reliever had allowed five runs — three earned — on only two hits with three walks.

“I’ve seen him pitch better,” Orioles manager Dave Trembley said. “And when Sarfate came out of the game, our bullpen didn’t back him up.”

Derek Jeter and Abreu drew one-out walks in the first before A-Rod roped a base hit to right field. Nick Markakis tried to nab the Yankees’ captain at home, but his throw sailed high and Abreu followed to the plate, deftly sliding around the tag of catcher Guillermo Quiroz.

Moments later, Rodriguez came home on a passed ball to make it 3-1.

The Orioles got one back in the third on an RBI single by Markakis, but the Yankees wasted no time — and seemingly no energy — in pulling away.

Abreu drove a 2-1 pitch from Sarfate off the foul pole in right with Johnny Damon aboard to make it 5-2 in the third. New York added four more in the sixth, getting run-scoring hits from Jason Giambi and Nady. Erratic reliever Fernando Cabrera also issued a bases-loaded walk to Melky Cabrera and threw a wild pitch to Jeter, handing the Yankees a 9-2 cushion.

Abreu added a solo shot in the seventh for his 12th career multihomer game and first as a member of the Yankees, and Rodriguez followed with a homer to right.

Juan Castro hit a pinch-hit homer in the eighth for Baltimore, his first of the year.

The teams became testy in the seventh when Yankees reliever Edwar Ramirez threw his first pitch over the head of Kevin Millar. Evidently thinking the pitch was in response to A-Rod getting plunked Tuesday night, plate umpire Mark Wegner immediately ejected Ramirez.

Orioles reliever Alberto Castillo hit Molina in the eighth but the pitcher remained in the game without so much as a warning, drawing a hearty round of boos from the crowd.

“He intentionally threw it behind his head,” Wegner said of Ramirez. “It was a done deal.”