Even with his hot start, Jason Martinson is still looking for ways to improve.
The Nationals' No. 20 prospect was 2-for-6 with a homer and four RBIs as Class A Advanced Potomac came up short against Frederick, 9-8, in 12 innings on Thursday.
Martinson got on the board early, doubling home a run in the first inning. In the seventh, the Texas native slugged his fifth homer of the season, a three-run shot that gave the Nationals a temporary 7-5 lead.
"Prior to going up, I was talking to our hitting coach Mark Harris. We were watching them warm up and he was keeping everything armside because he was a lefty," Martinson said. "There were two runners on. I was expecting offspeed and sat back and was able to put a good swing on it."
The 24-year-old shortstop has gotten off to a hot start this season, batting .327 with five homers and 15 RBIs for Class A Advanced Potomac. He currently leads the Carolina League in RBIs and is tied in homers. In addition, his 13 runs scored leads the circuit.
"I'm just slowing things down, working with our hitting coach on approach and not missing that pitch that you get because the majority of the time you're going to get one, maybe two pitches to hit in an at-bat," he said.
Martinson, an organizational All-Star in 2012, was named the Carolina League Player of the Week for the period ending April 15. In the three games since, he's put up three consecutive two-hit performances and has scored four times in that period. While pleased with the hot start and the accolades, Martinson still feels there are parts of his game that need improvement.
"[I'm] very happy but there's still a lot of progress to be made with some other areas," he said. "It's a work in progress out there every day working with our hitting coach and defensively. Just trying to refine my game in any way possible to make that next jump.
"I've been striking out way too much for my liking, so I'm just trying to minimize the strikeouts and be more consistent in the approach that I have at the plate."
Billy Burns was 2-for-4 with three runs scored out of the leadoff spot and Cutter Dykstra plated a pair for Potomac.
Allan de San Miguel led off the 12th inning with his second homer of the game, providing the Keys with the winning run.
Eric Beaulac (2-0) picked up the win after allowing three hits over three scoreless innings of relief.
Colin Bates (0-2) yielded two hits, including a homer, over two frames for the loss.
Robert Emrich is a contributor to MLB.com. Follow him on Twitter @RobertEmrich.