TAMPA, Fla.

Alex Rodriguez erased any personal doubts about regaining his power with one big swing.

Rodriguez hit his first home run since returning to the Yankees following a drug suspension and Chris Capuano was forced out in the first inning by a quadriceps injury in New York’s 10-6 loss to the Boston Red Sox on Wednesday.

“I was very happy. I haven’t it a ball like that in a long time,” Rodriguez said. “Again, it’s early March. We’ll see what happens. You have to do that in New York, where it counts. It’s definitely a building block.”

Rodriguez hit a long drive to left-center on a 3-1 pitch from right-hander Brandon Workman leading off the fourth inning. Rodriguez has five hits in 11 at-bats (.455) this spring training. “Very happy,” Yankees cochairman

Hank Steinbrenner said. “I’m not surprised with the hitting. … It’s encouraging. Hopefully it continues.”

Rodriguez has seen the number of fans booing him decrease daily. He received a partial standing ovation after his homer.

“The great reception I’ve been getting from the fans, that’s been a pleasant surprise,” Rodriguez said.

The three-time AL MVP, who turns 40 in July, has not played a full season since 2007 because of a season-long drug suspension, operations on both hips and other injuries.

Rodriguez said a pregame talk with Yankees special adviser Gene Michael provided “good words of wisdom.”

“He asked me: Do I see anything?” Michael said. “I just told him I think he can hit. He knows how to hit. He just needs a lot of at-bats, but I think that’s coming. He’s already shown that he can get the bat to ball. He’s not far off.”

Rodriguez made his second start at third base and cleanly handled two chances in five innings. The Yankees say Chase Headley is their starting third baseman and Rodriguez will be primarily a designated hitter.

Capuano, the top candidate to be the Yankees’ fifth starter, left after hurting his right leg while covering first base on Brock Holt’s one-out grounder to first baseman Garrett Jones. Capuano underwent an MRI exam.

“I’d be surprised if he’s not down for a while,” Yankees manager Joe Girardi said.

Travis Shaw opened the third inning with a firstpitch homer off Yankees reliever Andrew Miller, and drove in two with a double during a four-run fourth.

Mookie Betts had three hits and is hitting .400 overall.

UP NEXT

Red Sox: Clay Buchholz is scheduled to face Pittsburgh RHP A.J. Burnett in today’s road game at Bradenton, Fla.

Yankees: Masahiro Tanaka is to make his first start tonight against Atlanta. The Japanese ace missed 2 1/2 months while rehabilitating a partially torn ulnar collateral ligament in his right elbow and returned for two late September starts.