Nationals trade Lester to Cardinals
Washington receives outfielder Lane Thomas in return.
Lester is a familiar name to Cardinals fans, having spent several seasons facing them with the rival Chicago Cubs.
The 37-year-old joined Washington on a one-year contract this offseason. In 16 starts with the Nats, he posted a 5.02 ERA and 1.56 WHIP with 51 strikeouts and 29 walks.
Thomas has spent parts of the last three seasons in the majors, working primarily as a pinch-hitter. The 25-year-old has five hits in 58 plate appearances this season but has drawn 10 walks.