OAKLAND, Calif. -- The Oakland Athletics hope Ted Lilly can turn their Big Three into a formidable quartet.

	Lilly

The A's acquired Lilly, a spot starter for the pitching-rich New York Yankees, in a three-team trade late Friday. The 26-year-old left-hander joins a rotation anchored by the talented trio of Mark Mulder, Barry Zito and Tim Hudson.

While leaving the mighty Yankees was something of a shock, Lilly was grateful to be joining a team that has a legitimate postseason shot.

"My first thought was I'm going to a team that wants to win, and win all the way,'' he said.

Lilly was expected to arrive in Oakland late Saturday and join his new team on Sunday. The A's say Lilly will be part of the starting rotation, throwing the futures of rookie Aaron Harang and Cory Lidle up in the air, probably until after the All-Star break.

"I'll let you know,'' A's manager Art Howe said, adding that Lilly would be in the bullpen for Sunday's game against the Kansas City Royals.

The A's sent minor league first baseman Carlos Pena and right-handed pitcher Franklyn German to Detroit Friday night for right-hander Jeff Weaver and cash.

The A's then turned around and sent Weaver to the Yankees for Lilly and two promising minor leaguers, outfielder John-Ford Griffin and right-hander Jason Arnold.

"Ted Lilly is someone we've tried to get for the last several years,'' A's general manager Billy Beane said. "It's a success for us for a number of reasons. We get a major league pitcher and we get top picks from the Yankees.''

Lilly is 3-6 with a 3.40 ERA in 11 starts and two relief appearances. On April 27 he pitched a one-hitter in a 1-0 loss at Seattle and on June 22 he pitched a three-hitter at San Diego for his first major league shutout.

"I had heard that he (Beane) was trying to acquire me earlier in the year -- but you don't really pay attention to trade rumors,'' Lilly said.

Lilly will likely take over Lidle's spot in the rotation.

A roster move to make room for the new pitcher was not immediately announced.

Lidle has struggled, going 2-7 with a 5.30 ERA in 15 starts, while Harang, the rookie of the lineup, has shown promise with a 3-2 record and a 2.43 ERA in his first seven starts.

Harang, called up from Triple-A Sacramento on May 25, started Saturday against the Royals.

"It's nice to know we have some depth in that starting position, which we haven't had all year,'' Howe said. "We were a little thin there.''

Already schooled by the likes of David Wells, Andy Pettite and Roger Clemens, Lilly said he was excited about the prospect of joining the A's.

"You see watching them from the dugout that these guys play hard,'' Lilly said.

Both Howe and Beane said it was tough to let go of Pena, who opened the season for the A's at first -- Jason Giambi's spot before he bolted for the Yankees as a free agent in the offseason. In fact, Pena was touted as Giambi's heir apparent at first.

While Pena got off to a fast start, batting .264 with seven homers and 16 RBI in April, he fell off in May, batting .108 in 14 games before he was sent down to Triple-A Sacramento.

"Originally we intended to have Pena be here for a long time,'' Howe said. "He just didn't take advantage of the opportunity. That's not to say he won't be a great player, he just needs a little time.''