In return, the Orioles received pitching prospects Anthony Nunez (NYM No. 14) and Chandler Marsh.
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Mullins is slashing .229/.305/.433 with 15 home runs, 49 RBI, and 14 stolen bases in 91 games this season. The stellar defensive centerfielder will now join a New York Mets team looking to contend for the World Series.
Mullins is currently on a one-year deal and will be an unrestricted free agent after the end of the season.
Nunez is tossing a stellar 1.58 ERA in 32 games of relief, giving up just seven earned runs on 15 hits in 40 innings, striking out 60 batters while walking 17. Opponents are hitting just .119 off the 24-year-old in Double-A this season.
Marsh has a 2.57 ERA in 33 games as a relief pitcher in High-A ball this season. The 22-year-old has given up just 12 runs on 19 hits in 42 innings, striking out 52 while walking 17. Opponents are hitting .133 off Marsh this season.