In exchange for Espinosa, the Nationals received two prospects: right-handed pitchers Kyle McGowin and Austin Adams.
Espinosa was reportedly unhappy with the Nationals following their trade for center fielder Adam Eaton. The deal effectively moved Trea Turner, who was the Nationals' primary center fielder for the back half of the 2016 season, to shortstop and Espinosa to the bench.
As for Washington, as noted above, Espinosa became a bench piece that they found expendable. McGowin nor Adams are top-flight prospects, though they should help add depth to a farm system that was recently drained with the move for Eaton.
The 29-year-old Espinosa hit .209/.306/.378 with 24 home runs and 72 RBI over 601 plate appearnaces in 2016. According to FanGraphs, he was worth 1.7 Wins Above Replacement; Espinosa is an underrated defender, something that is not a new phenomenon for him, having posted 48.0 defensive rating above average for his career, as per FanGraphs.
Espinosa was tendered a contract by the Nationals earlier this offseason, and he is eligible for arbitration for the third and final time. This means that he will be a free agent at the end of next year.
The 25-year-old McGowin posted a 5.83 ERA and a 125-50 K/BB ratio over 154 innings for Double- and Triple-A last year. He was rated as the Angels' No. 16 prospect, per MLB.com.
As for Adams, he is also 25. In 2016, he spent most of his time in Double-A, where he posted a 3.05 ERA and a 63-24 K/BB ratio over 44.1 innings pitched. Adams is not rated among the Angels' Top-30 prospects.