BOSTON – In spring training, you could see the difference in Jacoby Ellsbury.

Ellsbury used to bounce through the clubhouse, whether it be at Hadlock Field or Fenway Park, offering a smile or a quick hello.

But that changed.

Ellsbury walked through the spring training clubhouse at Fort Myers, Fla., last March with eyes forward, all business.

The body language said everything. Ellsbury, the man with the swift feet, dependable swing and flashy glove, carried something else into the 2011 season: a mighty chip on his shoulder.

Ellsbury’s desire and toughness were questioned last season, an injury-filled year that had him confronting the Red Sox doctors while hearing doubts about his dedication.

If that chip has been motivation for Ellsbury, it’s worked wonderfully.

Ellsbury continued what may end up being an MVP season Wednesday night, going 2 for 5 with a double and a go-ahead, two-run homer in the seventh inning of Boston’s 9-5 victory over the New York Yankees.

It was Ellsbury’s 24th home run, four more than his career total. He is batting .313 with 35 doubles, 36 stolen bases, 84 RBI and 97 runs scored.

“He’s been great all year long. Nothing he can’t do on a baseball field,” second baseman Dustin Pedroia said. “We’re glad he’s on our team. He’s a force at the top of the lineup.”

Ellsbury was part of the vaunted 2005 draft. He finished his first pro season in 2006 in Portland. He was spraying champagne that September as a member of the Eastern League champion Sea Dogs.

Ellsbury began 2007 in Portland and was again spraying champagne at the end of the season, this time in October with the major league champion Red Sox.

Ellsbury continued to develop, although Boston tried a questionable experiment in 2010, signing free-agent center fielder Mike Cameron and moving Ellsbury to left field. He played the good soldier and moved over quietly.

The trouble began when Ellsbury suffered fractured ribs on April 11 in a collision with third baseman Adrian Beltre.

Ellsbury tried to come back and played a couple of rehab games in Portland that May. But he did not sound confident, saying he was still in pain.

“Even when I get my heart rate up and start expanding my lungs (the pain is there) the breaks were right at my chest,” Ellsbury said during his rehab in Portland.

Ellsbury made it back to the majors and reinjured his ribs. Red Sox doctors said it was a new break. Ellsbury said it was a previous break that went undetected. The feud was on.

Ellsbury went back on the disabled list. Radio talk shows were full of calls that Ellsbury was soft.

Teammate Kevin Youkilis questioned why Ellsbury was spending time at a training facility in Arizona instead of staying with the team.

With all the optimism at the start of this season, Ellsbury was a question mark.

He came back healthy and focused.

“Last year was very frustrating for him,” outfielder Josh Reddick said. “For him to come back and have a huge year after an off year like that especially with an injury in the section of your body where it’s hard to adjust and come back strong.

“He did a really good job in the offseason working out, and it’s showing.”

Ellsbury was not immediately available for comment after the game. He traditionally is one of the last players to appear in the locker room and is rarely quoted in a morning newspaper.

Red Sox Manager Terry Francona does not care how often Ellsbury chats up the media. Francona likes what he sees on the field, especially with Ellsbury’s new-found power. Ellsbury’s home run Wednesday was his first to the opposite field.

“We probably would not have seen that a couple of years ago,” Francona said. “But he stays back now. He stays balanced. Balls that may have been doubles or outs now turn into home runs.

“I think he’s getting more confident.”

Confident, with an attitude?

“I think all spring, whether it was a chip on his shoulder, he was feeling like he had something to prove,” Francona said.

“He has certainly done that — and then some.”

Staff Writer Kevin Thomas can be contacted at 791-6411 or at:

kthomas@pressherald.com

Twitter: ClearTheBases