Washington ? Livan Hernandez was traded by the Washington Nationals to the Arizona Diamondbacks on Monday for a pair of minor-league pitchers.

The 31-year-old Hernandez is 9-8 this season with a career-high 5.34 earned-run average in 24 starts. The right-hander has been hampered by a sore knee for most of the season but had the latest in a string of strong outings Sunday, allowing two runs over seven innings at San Diego.

“Obviously, it’s tough to trade a Livan,” Washington general manager Jim Bowden said. “We love Livan, but we’re not here to win tomorrow. We’re here to win for the long term.”

The Nationals received two 23-year-old prospects: right-hander Garrett Mock and left-hander Matt Chico. Both will report to Washington’s Double-A affiliate, Harrisburg of the Eastern League.