The Red Sox acquired Kotsay for minor-league outfielder Luis Sumoza, a mid-level prospect.

To complete the deal, Kotsay waived his no-trade clause for the Red Sox, one of eight teams on his no-trade list according to his contract.

Kotsay will receive a $325,000 assignment bonus for waiving his no-trade protection.

Kotsay was drawing interest from the Phillies, too, according to major-league sources.

Both teams are dealing with injuries to left-handed hitting outfielders.

The Red Sox on Tuesday placed right fielder J.D. Drew on the disabled list. Drew, suffering from a back problem, had missed Boston's previous six games.

Kotsay was scratched from Tuesday night's starting lineup, raising speculation that a trade was pending. Kotsay then pinch hit and walked in the ninth inning.

"I'd have to say it's my weirdest night as a professional in the big leagues," Kotsay said after the game. "I've never been scratched for that type of reason.

"I knew there was a possibility, so it wasn't a complete shock when I got called in and was told I would be scratched from the lineup due to precautionary reasons. The club was in discussions for possibly moving me."

Kotsay thought ahead to possibly joining the Red Sox.

"If that's the case, if I'm moved to a club that has postseason possibilities, you can't be disappointed as a player," he said. "I've had a lot of fun here and I've been happy with Bobby (Cox) and the organization."

The Red Sox's attempt to acquire the Padres' Brian Giles, another left-handed hitting outfielder, collapsed earlier this month when Giles invoked his no-trade clause to Boston.

Kotsay, who turns 33 on Dec. 2, has been hot in August, posting an .856 on-base/slugging percentage, his highest of any month this season.

"He's going to be a great addition. He's one of those leader-type guys," Red Sox pitcher Josh Beckett said.

Boston assumes the balance of his $8 million salary, which would amount to slightly more than $1.5 million.

The Braves did not plan to offer salary arbitration to Kotsay, who is a free agent at the end of the season.

Kotsay missed all of June due to a lower back strain, but since then has appeared in 40 of the Braves' 48 games.

For the season, he is batting .289 with a .338 on-base percentage, six home runs and 37 RBIs in 344 plate appearances.

To make room for Kotsay on the roster, Boston designated infielder-outfielder Joe Thurston for assignment. Thurston was called up Tuesday from Triple-A Pawtucket.

The 20-year-old Sumoza hit .301 in 51 games for Class A Lowell of the New York-Penn League this season.

Information from The Associated Press was used in this report.