Nathan Karns established his credentials as a big-time strikeout pitcher last season with Class A Hagerstown and Class A Advanced Potomac, combining to fan 148 batters over 116 innings.
On Saturday, he showed he should be able to do much more of the same now that he's with Double-A Harrisburg.
Taking the hill in the first game of a doubleheader, Karns recorded a career-high 13 strikeouts in a seven-inning complete game as the Senators beat the Altoona Curve, 4-1.
"He gave up those hits in the first and I think he beared down and started throwing some balls down, threw some really good breaking balls and changeups," Harrisburg manager Matt LeCroy told the (Harrisburg) Patriot-News. . That just shows you the stuff that he's got and his ability to go through a pretty good lineup and do it pretty easily," Senators manager Matt Lecroy told the (Harrisburg) Patriot-News. "Just happy he was able to finish it. ... I think he got stronger. His fastball got a little bit better as the game went on and his breaking ball was pretty sharp."
It was the second strong start in a row for the Nationals' No. 6 prospect. He opened the season on April 8 by allowing seven runs on seven hits, including a pair of homers, over 3 2/3 frames against New Britain. The Texas Tech product followed that up by striking out eight over five scoreless innings at Altoona, then mastered the Curve again Saturday.
The 25-year-old right-hander fanned 10-plus on five occasions last year and his total of 148 was tied for the 25th in the Minor Leagues. He also tossed the fewest innings of anyone who ranked in the top 30, averaging 11.48 strikeouts per nine innings.
"He's got three plus-pitches," LeCroy told the newspaper. "Just a solid outing. It was good for him, he needed it. I was glad he was able to go seven."
A 2009 12th-round Draft pick, Karns has progressed rapidly through the Washington system since undergoing surgery that sidelined him for the entire 2010 season. He came back in 2011 and tossed 55 1/3 innings between the Rookie-level Gulf Coast League and short-season Auburn in the New York-Penn League.
His 13 appearances with Potomac last season were the most he's registered at any level before earning a promotion.
"The big right-hander really put his torn labrum behind him in 2012, pitching at two levels while leading the organization in ERA, batting average against, strikeouts and WHIP," MLB.com's Jonathan Mayo wrote of Karns' season. "It was encouraging that his walk rate went down after his promotion without sacrificing anything along the way."
In three outings this year, Karns has a 4.60 ERA, 24 strikeouts and only five walks in 15 2/3 frames.
Randolph Oduber slugged a three-run homer for the Senators, who erased a five-run deficit in the nightcap before dropping a 9-7, 11-inning decision.
Charles Cutler delivered a two-run double in the 11th for the Curve.