Casey Kotchman spent summers from age 7 through 10 on long rides with dozens of older guys all over Washington. He was traveling from Boise, Idaho, tagging along with the low-level minor league team managed by his father, Tom.

"I enjoyed all the bus rides. I spent a lot of time growing up here in the Northwest," Kotchman said Thursday.

He's all grown up now upon his return to the region. And, no, he doesn't have to take the bus anymore.

The Mariners finalized their trade with the Boston Red Sox on Thursday that brings the 26-year-old defensive whiz first baseman to Seattle for outfielder Bill Hall, a player to be named and cash.

Kotchman, who stands to get a raise soon from his $2,885,000 salary from last year, passed his physical to complete the deal which had been agreed to on Tuesday.

The trade means Seattle won't bring back slugging first baseman Russell Branyan. The Mariners feared the free agent might not be completely healed from a disk issue in his back from late last season and may not be worthy of the multiyear contract he wants.

"We did our due diligence on a lot of fronts. We left no stone unturned," is all Seattle general manager Jack Zduriencik said when asked why Branyan isn't being retained.

Kotchman fits Zduriencik's plan to rebuild the rising Mariners through defense, pitching and youth. He's less of a power hitter but is eight years younger and a better defender than Branyan. Zduriencik also likes that Kotchman doesn't strike out much _ 43 is his career high.

"Talking to Theo (Epstein, the GM of the Red Sox), he told me, 'I love Casey up to the plate against anybody, because he grinds out at-bats,'" Zduriencik said.

The Red Sox have an excess of veteran corner infielders following the signing of former Seattle third baseman Adrian Beltre. They tried to trade third baseman Mike Lowell to Texas for catcher Max Ramirez last month, but that deal fell through when Lowell needed thumb surgery. Boston would still like to deal Lowell.

Kotchman is a .269 career hitter who has never hit more than 14 home runs in a season and is known for defense. He joined Boston on July 31 in a trade with Atlanta and played 39 games with the Red Sox.

The 30-year-old Hall hit .200 with two homers and 12 RBIs in 34 games with Seattle last season after a trade with Milwaukee on Aug. 19.

The player to be named is expected to be a minor leaguer.

Epstein did not immediately respond to an e-mail from The Associated Press on Thursday night.

Kotchman has not made an error over his last 185 games and last year became just the third first baseman in major league history with a perfect fielding percentage while playing at least 108 games at the position. He'll fit in with fellow fielding standouts Jack Wilson at shortstop, Ichiro Suzuki in right field and Franklin Gutierrez in center on what looks to be one of baseball's best defenses.

With co-ace Cliff Lee arriving in a blockbuster trade from Philadelphia to join AL Cy Young Award runner-up Felix Hernandez, Zduriencik thinks his pitching and defense will compensate for the power Seattle won't have with Branyan and his 31 home runs from '09 gone.

Zduriencik, entering his second season as the Mariners' GM, has known Kotchman since he was in junior high in Florida, through his dad, who went on to work as a scout and in player development for the Angels. Mariners scouting director Tom McNamara was an area scout around Seminole, Fla., when Kotchman was a high school star there.

And Mariners manager Don Wakamatsu and bench coach Ty Van Burkleo were minor league instructors with the Angels when Kotchman began his professional career with that organization.

Plus, the busy Mariners _ who last season became the 13th team since 1901 to have a winning record immediately after a 100-loss season _ recently signed free agent Chone Figgins. The All-Star third baseman was a teammate of Kotchman's in Los Angeles until midway through the 2008 season, when the Angels sent Kotchman to Atlanta in the Mark Teixeira trade.

"I'm excited to be here. That's an understatement," Kotchman said, wearing a navy blue suit to match the team colors of his fourth major league club in three years. "It helps to have familiar faces around. Certainly, there's a comfort level here."

Kotchman is the fifth Mariners player eligible for arbitration, joining closer David Aardsma, Gutierrez, reliever Mark Lowe, and Hernandez _ with whom Seattle is also negotiating a long-term deal. The Mariners also are close to announcing a $20.5 million, four-year contract for Gutierrez.

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AP Sports Writer Jimmy Golen in Boston and AP Baseball Writer Janie McCauley in Alameda, Calif., contributed to this report.