House hit .306 with 25 doubles, 18 homers and 60 RBIs in 2008 for Round Rock, the Astros' Triple-A affiliate.
"They were the most aggressive about approaching me and wanting me, and I thought it was the best opportunity to play," the 29-year-old House told the paper. "It also seems they are going to give me the best chance to catch and find more ways to get in the lineup."
House was originally drafted by the Pirates in the fifth round of the 1999 First-Year Player Draft. He has appeared in 32 big league games over parts of five seasons for the Pirates, Astros and Orioles.
Steve Gilbert is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.