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The Washington Nationals today selected right-handed pitcher Craig Stammen from Syracuse of the Triple-A International League and optioned right-handed pitcher Garrett Mock to Syracuse. Nationals Assistant General Manager and Vice President of Baseball Operations Mike Rizzo made the announcement.

Stammen is slated to make his big-league debut as the starter in tonight's series finale against Pittsburgh. The 25-year-old, who posted a 4-2 record in seven starts with Syracuse, ranks seventh in the International League with a 1.80 ERA (8 ER/40.0 IP). In three May starts, he went 1-1 and allowed only two earned runs in 17.0 innings en route to a 1.06 ERA.

With the addition of Stammen, the Nationals' rotation currently sports four rookies -- Shairon Martis (22), Jordan Zimmermann (22), Ross Detwiler (23) and Stammen (25) -- and John Lannan, a 24-year-old who has made just 46 career big-league starts.

Stammen was selected by Washington in the 12th round of the 2005 First-Year Player Draft out of the University of Dayton.