Chatwood has a strained left hamstring and is on the DL retroactive to March 29. He was injured running out a triple in a spring training game.
Chatwood went 8-5 with a 3.15 ERA last season.
Lyles, who went 7-9 with a 5.59 ERA last season with the Astros, was acquired in a trade along with Brandon Barnes for Dexter Fowler.
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