The Washington Nationals traded one of their best pitchers, Jason Marquis, to the Arizona Diamondbacks for a 21-year-old minor league shortstop.
Walters has been named to the All-Star team in each of his two seasons in Arizona's system, In the Midwest League in 2011 and the Northwest League last year, according to a statement from the Nats.
In his two professional seasons, Walters has been hitting .302 (192-for-636) hitter with 45 doubles, 10 triples, 13 home runs and 26 stolen bases in 166 games.
Marquis, 32, went 8-5 with a 3.95 ERA in 20 starts this season with Washington.
In his pro debut with Yakima in 2010, Walters hit .302 with 26 extra-base hits, 43 RBIs and 14 stolen bases in 69 short-season Single-A Northwest League games. He's 6-foot-3, 195 lbs and a switch hitter.
So far this season, Walters is again batting .302 (83-for-275) with Single-A South Bend. He ranks among Midwest League leaders in runs (tied second, 69), hits (third, 109), total bases (third, 175) and extra-base hits (fourth, 42).
Walters played at the University of San Diego, and was drafted by Arizona in the ninth round of the 2010 First-Year Player Draft.
Walters has been assigned by Washington to Potomac of the Single-A Carolina League