Lumsden, 25, went 3-13 with a 7.21 ERA in 28 games, including 18 starts, for Triple-A Omaha in 2008. He is currently playing in the Puerto Rican Winter League, for the Gigantes de Carolina, and is 0-1 with a 9.64 ERA in four games (three starts). He takes a spot on the Astros' 40-man roster, with an invitation to Spring Training.
"Tyler's numbers weren't good this year, but our guys like his arm," general manager Ed Wade said. "He's a big, strong lefty, and he's only 25 years old. He has remaining options, so we'll get him into Kissimmee, [Fla.], evaluate him and give him a chance to compete. At the very least, Tyler provides us with some more young depth."
Lumsden figures to get a long look next spring. If the Astros are unable to re-sign free-agent starter Randy Wolf, they would have only four returning left-handers on the 40-man roster: Wandy Rodriguez, Tim Byrdak, Wesley Wright and Polin Trinidad.
Bringing in Lumsden has no effect on the club's ongoing efforts to re-sign Wolf or right-handed setup man Doug Brocail.
"This is one of those 'fringy' deals, where you hope it develops into something," Wade said. "This is the normal course of stuff that we do in the offseason -- try to find that diamond in the rough."
In 95 Minor League games, Lumsden is 26-25 with a 4.89 ERA. Selected by the Chicago White Sox as a sandwich pick between the first and second rounds of the June 2004 Draft, he missed all of 2005 following bone spur surgery. He was acquired by the Royals, along with Dan Cortes, in exchange for Mike MacDougal on July 24, 2006. He was designated for assignment by the Royals on Thursday.
Lumsden, who stands 6-foot-4, features a fastball that tops out at 94 mph, an average curveball and changeup, and a developing cutter. The Astros believe that he hasn't flamed out yet, especially since tall throwers and lefties sometimes take a little longer to pan out.
"I'd like to think that he's going to develop into the next Steve Carlton," Wade joked about Lumsden, who has a similar build to the Hall of Famer. "But I'm not ready to make that prediction at the moment."
Nick Zaccardi is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.