OAKLAND, Calif. - The Oakland Athletics filled their second key position in five days Sunday, acquiring first baseman Ike Davis and international bonus slot 86 from the Pittsburgh Pirates in exchange for international bonus slot 27.

Oakland, which lost in the AL wild-card game 9-8 in 12 innings to Kansas City, signed designated hitter Billy Butler to a $30 million, three-year contract Wednesday. Butler also is likely to play some first base, where catcher Stephen Vogt was a regular down the stretch because of a foot injury that limited him.

A's manager Bob Melvin, attending the San Francisco 49ers' 17-13 win over the Washington Redskins in Santa Clara, said he's unsure how the lineup might look.

"We'll see how it plays out at first. We're always looking for depth," Melvin said. "It's always nice to get a couple of guys early in the off-season that you feel like could help you."

The 27-year-old Davis began last season with the New York Mets and batted .208 with a home run and five RBIs in 12 games before Pittsburgh acquired him April 18 for pitchers Zack Thornton and Blake Taylor.

A left-handed hitter, Davis then batted .235 in 131 games for the Pirates, finishing 2014 with a .233 overall batting average and 11 homers and 51 RBIs in 143 games.

The A's designated outfielder Andrew Brown for assignment to clear roster room for Davis.

Davis was designated for assignment Thursday. Had he remained on Pittsburgh's roster past Dec. 2, he would have been eligible for salary arbitration and in line to receive a large raise from his $3.5 million salary.

Butler batted .271 with nine home runs and 66 RBIs in 151 games this year, 108 of those as a DH.

Now, general manager Billy Beane is focused on finding a shortstop considering Jed Lowrie is a free agent. Though Beane said Andy Parrino could be an option from within.

"It's still early in the off-season, but it's not a robust market, in our opinion," Beane said after the Butler signing. "Other clubs are in pursuit of shortstops and middle infielders."