The 21-year-old right-hander -- who had been the youngest player in the American League this season until Trout's callup -- was 5-5 with a 3.62 ERA through 17 starts. Part of the reason for the move was that Chatwood was not slated to make any more starts for the Angels before the All-Star break, said manager Mike Scioscia, leaving him with a long inactive period if he were to stay on the big league roster.
He'll be called back up following next week's Midsummer Classic.
"I think it's good for him to stay fresh and get a start in Triple-A, which he wouldn't get here because of the All-Star break," Scioscia said. "We're excited about where Tyler is, and we just think it's a better maintenance program for him right now."
Chatwood is expected to throw a bullpen session on Saturday, and then start for the Bees at Tacoma on Thursday.