Beckham has batted only .221/.263/.336 this season but has posted an .803 OPS against lefties (compared with .530 against righties).
"Not having a great year with the bat, but really wearing out left-handed pitching," said general manager Jerry Dipoto, who put a claim on Beckham before working out a trade. "We feel like it's a real nice platoon advantage for us."
The Angels finish the season with 43 games in 45 days, with their only off-days coming on Sept. 1 and 25. Beckham's presence will allow manager Mike Scioscia to give second baseman Howie Kendrick, third baseman David Freese and shortstop Erick Aybar a day off when needed, while keeping utility infielder John McDonald in his role as a late-game defensive replacement.
Beckham, 27, is controllable through 2015 and is making $4.175 million this season, with the Angels picking up the prorated portion of that.
The No. 8 overall pick in the 2008 First-Year Player Draft, Beckham -- a natural shortstop who has mostly played corner infield in the Majors -- has a career .244/.306/.374 slash line through six years in the big leagues. He showed promise in his first season, batting .270 with 14 homers and 63 RBIs to finish fifth in American League Rookie of the Year voting, but he struggled offensively over the next five years.
The Angels are hoping to maximize Beckham's abilities in a part-time role.
"I think the benefit with our team is that you don't need him to take four at-bats a game, seven days a week," Dipoto said. "You just need him to be a part of the team."
Alden Gonzalez is a reporter for MLB.com. Read his blog, Gonzo and "The Show", and follow him on Twitter @Alden_Gonzalez. This story was not subject to the approval of Major League Baseball or its clubs.