The A's traded reliever Marc Rzepczynski on Thursday to the Washington Nationals, who were looking for a lefty to boost their bullpen as they prepare for the stretch run.
In return, the A's received minor league middle infielder Max Schrock, a 21-year-old who has enjoyed a strong season at Single-A that was gaining him notice in the Nats' farm system.
Rzepczynski, who came to Oakland in the same deal that brought Yonder Alonso from San Diego, is set to be a free agent at the end of this season. He went 1-0 with a 3.03 ERA in 55 games for the A's.
Schrock, a 13th round pick in 2015, has split this season between low and high Single-A, hitting .333 with 31 doubles, nine homers and 68 RBI in 120 games combined.
He was rated the Nats' No. 17 prospect by Baseball America. His bat is considered his strong point, and he's played the majority of games this season at second base, with two at shortstop.