The St. Louis Cardinals signed left-handed year contract on Thursday.
The 35-year-old ended the 2011 season with Colorado after beginning the year with Philadelphia. In 36 combined games last season, Romero went 1-0 with a 4.01 earned run average.
Romero has compiled a 34-28 record with seven saves and a 4.07 ERA in 664 career games with the Twins, Angels, Red Sox, Phillies and Rockies.
"Romero is a proven lefty specialist, who has been a valuable bullpen piece for winning teams throughout his career," said Cardinals' senior vice president John Mozeliak. "We felt that it was important to maintain versatility and depth within our bullpen and we feel that J.C. will be a solid addition."
Romero leads major league left-handers in games pitched from 2002-2011 with 633, while his 517 innings pitched during that time span ranks second among lefty relievers.
In addition, he has made six career postseason appearances, three with the Minnesota Twins and three with Philadelphia, and he pitched for Puerto Rico in both the 2006 and 2009 World Baseball Classics.