The A's swung a trade Sunday night for San Diego Padres outfielder Scott Hairston in exchange for minor league pitchers Ryan Webb and Craig Italiano and a player to be named.

Hairston, 29, was playing mainly center field and occasionally left field for the Padres. He's expected to join the A's in time for tonight's series opener in Boston. He's likely to enter the lineup immediately in center field, assistant general manager David Forst said.

Hairston, who throws and bats right-handed, was hitting .299 with 10 home runs and 29 RBI in 56 games for San Diego. He hit a career-high 17 homers last season.

"Hairston's a guy we've liked for quite some time," Forst said. "He's a right-handed power guy, which is obviously something we haven't had much of over the years."

Forst indicated center fielder Ryan Sweeney could shift over and play some right field, a position he played predominantly last season.

The A's will have to make a roster move to clear space for Hairston. Outfielder Travis Buck is a possible candidate to be sent to Triple-A Sacramento.

While some may speculate that adding Hairston makes it easier to withstand a possible trade of free-agent-to-be Matt Holliday, Forst said that wasn't the team's thinking.

"We made this deal independent of anything else that may or may not be going on," Forst said. "I'm not going to guess what or if anything comes next. (But) I wouldn't read too much into it as far as something else coming down."

Webb, a 23-year-old right-hander who was the A's fourth-round draft pick in 2004, was 7-1 with two saves and a 4.34 ERA at Sacramento. Webb was seen by the A's as one of their better bullpen prospects.

Italiano, an A's second-round pick in 2005, was struggling at Single-A Stockton with a 5-6 record and a 5.63 ERA. The 22-year-old right-hander had 75 strikeouts in 762/3 innings.