"We anticipate it will be a better pitch," farm director Keith Lieppman said. "Last year, it was down in the 60-mile-per-hour range. Now it is up into the 70s with a better bite."
With the higher-octane curve, the Athletics are highly optimistic about Leon's future. The 20-year-old reliever from Mexico already is pitching for Double-A Midland, and he is showing he can handle the competition.
Leon throws both two- and four-seam fastballs, with his high velocities in the 88-92 mph range, plus a changeup and a cutter.
"He's got a little sneaky quickness about him," pitching coordinator Gil Patterson said. "His ball's tough to pick up. He's also a very tough competitor."
Leon grew up in Culiacan, Mexico, and was pitching for Saltillo of the Mexican League when A's roving minor league instructor Juan Navarrete recommended him to the organization. They brought him to spring training in 2008, then purchased his contract with the stipulation that he would pitch for Saltillo that year.
He went 2-1, 4.30 in 13 relief appearances for Saltillo. He also appeared in 20 games for high Class A Stockton last season, posting a 2.86 ERA in 28 innings.
"I never met the scout from the A's who signed me," Leon said. "They bought my contract from Saltillo."
Leon was thrown into the U.S., where he had much to learn. He has been taking crash courses in English, and he has learned the language well enough to communicate with his teammates and the reporters who stop by. He also has changed his delivery, from a drop-and-drive to a shorter stride.
"A lot of his pitches were flat," Lieppman said. "He's worked well at getting more of a downward angle. You can see the improvement."
The A's toyed with the idea of making him a starter in spring training, but then decided to keep him in the bullpen. Leon had been strictly a reliever in his two-plus seasons with Saltillo.
"I haven't started since Little League," he said.
The A's regard Leon as both canny and competitive, and they believe he could become an effective relief option in a couple of years.
• Midland outfielder Javier Herrera broke the hook of his hamate bone and was expected to miss about six weeks. Once considered a top prospect, a series of injuries have stalled his progress.
• Midland second baseman Corey Wimberly tore a ligament in his thumb while sliding into home plate, and Stockton righthander Dan Thomas went down with a torn labrum in his shoulder.