"I threw slider, threw it wrong," he said. "It never really popped. It hurt instantly. I knew something was wrong."
Nathan the Texas A&M signee, suffered two partial tears to his ulnar collateral ligament in his right elbow. His option -- a long rehab or Tommy John surgery.
"I wanted to get back and plus, everyone says it's a lot better than the rotator cuff surgery," he said. "Everybody was coming back stronger."
"He did a little research on it and talked to some different people. He jumped into his rehab as a champion and is really impressive to watch him work," said Alvin Coach Mike Rogers.
Nathan bounced back with a 10-1 record this season. What was ground breaking in the 70's is now common place even among high school pitchers. Hundreds of young pitchers undergo Tommy John surgery each year.
It's taken Nathan a while to get back up to speed, but he's actually throwing hard now than ever before.
"What was your fastest time before?" we asked him.
"96," he told us.
"I'm hitting 98," said Evaldi.
"I can probably tell you which one it was because I remember thinking that one got there," said Alvin catcher Travis Snider. "That one got there quick."
Evaldi and the Yellowjackets are better than ever.