PORT CHARLOTTE — Jesse Hahn is a hard-throwing right-hander with a fastball that routinely reaches 95 mph. His other pitches — a curve, slider and changeup — tend to cross the plate with uncanny and merciless accuracy.Hahn uses that arsenal to mow down batters with efficiency as a starter for the Charlotte Stone Crabs, the Rays' advanced Class A affiliate. His statistics are impressive: a 1.23 ERA with 43 strikeouts in 44 innings. Those numbers are a big reason Hahn will be part of the pitching staff for the South Division in tonight's Florida State League All-Star Game in Dunedin.His selection comes despite not recording a win in 13 starts.That's by design. Three years ago, Hahn had elbow surgery, and to protect his long-term baseball health, the Rays imposed a limit on the number of innings he would pitch in each start. Hahn went three innings each outing to begin the season. He has since been extended to four. But no matter how well he pitches when he starts, he won't meet the five-inning requirement to qualify for a win."I can't go into games thinking about the fact I'm not going to get a win," Hahn said. "My whole mind-set is to go out there and post zeroes. That's my job."At Virginia Tech, Hahn was a prized pitching prospect who had first-round potential. But in his final start of the 2010 season, he lasted only three innings. He tore the ulnar collateral ligament in his right elbow, which required elbow-ligament replacement, or Tommy John, surgery.Hahn tumbled to the sixth round, where the Rays selected him in the 2010 amateur draft. They gave him a $525,000 signing bonus despite a surgical detour that would require Hahn to miss the 2011 season."I was real frustrated at the time," he said. "My injury happened two days before the draft. I didn't know where I would be selected or if a team would even take a chance on me. I'm just so thankful the Rays gave me an opportunity."Hahn went through a grueling rehab while watching others from his draft class climb the ladder of their organizations. One of Hahn's high school teammates from Connecticut, Matt Harvey, is now an established starter with the Mets."The delay was hard to deal with," Hahn said. "I knew it was going to be a long rehab, and a long time coming back. The biggest challenge was seeing people who I've grown up with for years progress a lot faster. I just knew I had to be patient."Hahn also had to relearn the craft of pitching. He redefined his mechanics, perfecting his command and location rather than having some personal duel with the radar gun."What basically led to the surgery was bad pitching mechanics," Hahn said. "We've cleaned all that up, and I've learned how to become a better pitcher, not just a thrower. I've also learned how to get through soreness and discomfort."It didn't take long for Hahn to become dominant again. Last season, he was 2-2 with a 2.77 ERA while striking out 55 batters in 52 innings at Class A Hudson Valley. This year, Hahn is more polished, posting a 22-inning scoreless streak that ended Thursday when he gave up three runs in four innings."Jesse has the stuff to move up pretty quickly," Stone Crabs manager Brady Williams said. "He's able to pitch in any situation, and he finds a way to make quality pitches. He's able to deal with the innings limit, and anything else that's thrown his way. He gets it. He understands what this is all about." Hahn is supposed to be stretched to five innings in the second half of the season, which will allow him to start picking up wins. There is no set timetable on when he will advance another level."I'm satisfied with how quickly I've been able to come back," Hahn said. "But I don't think I'll be completely satisfied until I make it to the big leagues."