The 28-year-old McClellan comes to Texas via St. Louis, where he has spent his entire professional career, going 19-23 with a 3.69 ERA in 261 games -- 17 starts -- since 2008.
The Rangers say their plan is to initially work out McClellan as a starter in camp, despite his lengthier history in the bullpen, where he compiled a 5.30 ERA over 16 relief appearances for the Cardinals last year.
McClellan's season ended May 18, as he was forced to undergo surgery on his right elbow and shoulder two months later. However, Texas says he is already throwing again and is expected to be at 100 percent for the start of Spring Training.
"Kyle has had success on winning clubs in a variety of roles -- starter, setup guy and swing man," Rangers general manager Jon Daniels said. "He'll be in the mix for any one of several spots on the staff. His versatility and makeup should be real assets to the club."
McClellan, who was placed on unconditional release waivers by St. Louis on Nov. 13, made at least 60 appearances each season from 2008-10. All of his starts came in '11, when he went 6-6 with a 4.21 ERA.
With the addition of McClellan, the Rangers now have 57 players on their Spring Training roster, including a full 40-man roster and 17 non-roster invites.
In other news, Texas also announced Tuesday that the club has signed left-hander Ryan Feierabend and righty Kevin Pucetas to Minor League contracts. Both will be in Minor League camp this spring.
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.