Valdes, 33, hails from Cuba but came to the United States in 2004, when he signed with the Cubs organization as a free agent. He has started and relieved in the Minors, and made one start for New York in 2010 as well. In his only Major League season, Valdes went 3-3 with a 4.91 ERA, 56 strikeouts, 27 walks and seven home runs allowed in 58 2/3 innings.
"We're trying to add some depth," Mozeliak said, "and more importantly, we certainly think he'll have a chance to compete for a job when he comes to camp."
The lefty had an extreme reverse platoon split in '10, shutting down right-handed hitters while getting blasted by left-handers. Righties batted .216 with a .339 on-base percentage and a .331 slugging percentage against Valdes, while lefties posted a line of .330/.366/.625.
However, in 36 Minor League innings in 2010, Valdes showed a more conventional split, holding left-handed batters to a .226 average while right-handers hit .265 against him.
The Cardinals are still likely to add a more established left-handed reliever to their bullpen. Currently, only Trever Miller is set as a lefty in the St. Louis relief corps for 2011. Still, Valdes provides some depth to an area of the club where depth had been lacking.
Matthew Leach is a reporter for MLB.com. Read his blog, Obviously, You're Not a Golfer and follow him on Twitter at @MatthewHLeach. This story was not subject to the approval of Major League Baseball or its clubs.