The Houston Astros made a move to shore up their defense behind the plate by trading within their own division.
The Angels, who trail the first-place Astros by 15½ games in the AL West standings, receive left-handed pitching prospect Patrick Sandoval in the deal.
"Martin has been a huge part of what we know has been a terrific year on the mound,'' Angels manager Mike Scioscia said. "There's no doubt that Martin had the respect of everybody, not only the coaching staff but the players, and contributed greatly to where we needed to be on the defensive side.''
This year, Maldonado leads all MLB catchers with a .444 caught-stealing percentage, catching 12 of 27 base stealers this season. His .994 fielding percentage is ranked fifth in baseball.
Offensively, the 31-year-old Maldonado, who will be a free agent at the end of this season, is hitting .223 with five home runs and 32 RBIs.
"I'm going to be a free agent. We haven't played the way we want to play, and today is business. They got to do whatever is best for the team,'' Maldonado said.
Maldonado said he was initially caught by surprise when he was informed of the trade but welcomes the opportunity to join the defending World Series champions.
"Playing against those guys, it's a team that they never give up,'' Maldonado said. "They compete from the first pitch to the 27th out, so I'm looking forward to learn more as soon as I get there about those pitchers and those guys.''
The Astros have been without starting catcher Brian McCann, who has been sidelined since having surgery on his right knee earlier this month. Max Stassi has been seeing the bulk of the time at catcher during McCann's absence.
Sandoval, 21, was 9-1 with a 2.56 ERA in two levels of the Astros' minor league organization this season. At the time of the trade he was with the Astros' High A team (Buies Creek) in the Carolina League.
The Angels selected the contract of catcher Francisco Arcia from Triple-A Salt Lake and also received international pool space from Houston.
The Astros designated catcher Tim Federowicz for assignment in a corresponding move.
The Associated Press contributed to this report.