The Washington Nationals added much-needed bullpen help to the mix for the stretch run. The team has acquired lefty reliever Marc Rzepczynski from the Oakland Athletics in exchange for minor league infielder Max Schrock. 

Rzepczynski, 30, is pitching to a 3.00 ERA and 1.72 WHIP in 56 games this season. With 36 innings under his belt, he's considered a specialist against fellow left-handed hitters. 

Though, the move comes at a surprisingly high cost. Washington parted ways with a top-15 organizational prospect in Schrock, who is hitting at a .333 clip with nine homers and 68 RBI at two Single-A levels on the season. Schrock was a 13th-round pick of the Nationals in last year's draft.