BOSTON — Things are going pretty well so far in the Bay State.

Ever since Jason Bay came to Boston in a deadline deal for Manny Ramirez, the low-key, un-dreadlocked left fielder has fit right in. Playing in his first pennant race and first postseason, Bay scored in every one of Boston’s first-round wins against the Angels, sliding home with the winning run Monday night as the Red Sox advanced to the AL championship series.

“I can’t imagine that it’ll get more intense than this,” he said while celebrating with teammates he has known only about two months. “But it will.”

Bay spent most of his first five seasons in Pittsburgh, playing for Pirates teams that never finished higher than fourth. So he was the happiest one around when the Red Sox went looking for a way to ditch Ramirez at the trade deadline, eventually working out a three-team deal that sent the disgruntled slugger to the Dodgers and brought Bay to Boston.

The happiest, that is, except for Ramirez.

The first World Series MVP in Red Sox history, Ramirez put up big numbers over 71⁄2 years in a Boston uniform, but also earned the better part of $160 million and precipitated enough clubhouse flareups to leave management wondering if he was more trouble than he was worth.

After years of ill-timed and sometimes suspicious absences from the lineup, the tipping point might have been a July at-bat when, called upon to pinch-hit on a day he expected to be off, he struck out on three pitches from Yankees closer Mariano Rivera without ever taking the bat off his shoulder.

Ramirez got what he wanted: Red Sox general manager Theo Epstein shipped him to the Dodgers in a three-team deal that brought Bay to Boston.

“Jason has had an impressive transition into a new league, a new clubhouse and his first pennant race,” Epstein said in an e-mail to The Associated Press on Tuesday, a day after the Red Sox earned a chance to play for the AL pennant against the Tampa Bay Rays.

“He knows himself really well as a player and as a person, and is comfortable with who he is. He’s not the type to put too much pressure on himself, or to change his behavior to try to be something he’s not. He hasn’t tried to replace Manny Ramirez, and we never asked him to do so. He’s been himself — a steady, productive all-around good player and great teammate.”

In Los Angeles, Ramirez propelled the Dodgers to the NL West title with a .396 batting average, 17 homers and 53 RBIs in 53 games. He went 5-for-10 with two home runs, three RBIs and four walks in the Dodgers’ division-series victory over the Chicago Cubs, then said, “I came, I did my job. I’m just blessed to be here.”

And Bay is blessed to be in Boston, where they are comparing the trade to the 2004 move that shipped out fan favorite Nomar Garciaparra in a four-team deal that brought the Red Sox Orlando Cabrera and Doug Mientkiewicz — key players in the title that ended the franchise’s 86-year World Series drought.

“The goal is to build a winning team — not necessarily an accumulation of the most recognizable star players,” Epstein said. “Those trades were made because, in our opinion, they improved our chances of winning the World Series.”

Bay has already helped Boston take the first step.

He hit a two-run homer in Game 1 to give the Red Sox the lead, then hit another in the second game. On Sunday night, he threw Torii Hunter out at second base when the speedy Angels outfielder tried to stretch a single into a double.

In the Game 4 clincher on Monday, Bay hit a one-out double in the ninth inning of a 2-2 game. When Jed Lowrie bounced a single through the hole between the first and second basemen, Bay motored around third and dove for the plate, sliding in headfirst to get his fingers on the plate for the winning run.

“The only thing I was thinking about was scoring,” Bay said. “I wanted to score so bad I almost fell down rounding third. I tried to run faster than my legs would go.”