OAKLAND -- Less than a day after allowing Kiko Calero to become a free agent by not offering the arbitration-eligible reliever a contract before Wednesday's 9 p.m. PT deadline, the A's reached agreement with Calero on a one-year deal for 2008.

Calero, who battled shoulder problems for much of last season and had the worst year of his five-year career, has been rehabbing at home in Puerto Rico for the past two months.

Acquired in the December 2004 trade that sent Mark Mulder to the Cardinals, Calero posted a 3.23 ERA and held opponents to a .212 batting average over 58 appearances in 2005. In 2006 he made a career-high 70 appearances and posted a 3.41 ERA with a .231 opponents' batting average.

Calero's shoulder problems limited him to 46 games in 2007 before he was shut down for the final month of the season. His ERA of 5.75 and opponents' batting average of .293 were by far the highest of his career.

Calero, who turns 33 in January, made $1.6 million last season. Financial terms of his new deal were not announced.