Oakland A's Top-51 Prospects: Arnold Leon

Our Oakland A's 2015 top-51 prospects list is out. Now find out more about the players on that list. In this piece, a close look at top-51 prospect Arnold Leon.

Name: Arnold Leon
Position: RHP
Height/Weight: 6’1’’, 205
Bats/Throws: R/R
Age: 26
How Acquired: Signed as an amateur free agent in 2008


Arnold Leon was a member of the Oakland A’s for one day during the 2014 season, but he didn’t get a chance to appear in a game before being sent back to Triple-A. The 2015 season could provide a more real opportunity for Leon at the big league level, however.


Complete Oakland A's Top-50 Prospect Index

A native of Mexico, Leon has been a member of the A’s organization since signing with the team as a teenager in 2008. During his seven years with the organization, Leon has overcome Tommy John surgery to become one of the more reliable and durable arms in the upper levels of the A’s minor league system.

Leon began his career as a 19-year-old pitching for High-A Stockton. For the first year of his career with the A’s, he was on a split-contract with his Mexican Summer League team, meaning that he pitched for Stockton for the first half of the year and Saltillo for the second half of the regular season. Leon then pitched in Mexico for Culiacan during the winter ball season. Although the A’s projected Leon to be a starter, they kept him in a relief role for most of his first two seasons with the organization in large part because they needed to limit his innings during the regular season due to his workload in the winter.

During the final six weeks of the 2009 season, Leon moved from the bullpen to the starting rotation with Double-A Midland. He pitched well in that role, posting a 1.76 ERA in seven starts. He struck-out 29 and walked eight in 30.2 innings. Leon looked poised to make a permanent move into the rotation in 2010.

"Anytime you can give Arnold the baseball and watch him pitch, it is fun to watch." - A's bullpen coach Scott Emerson.

Unfortunately, an elbow injury stalled those plans. Only three appearances into the 2010 season with Midland, Leon tore his UCL and was lost to Tommy John surgery. Whether the injury was due to his year-round workload or just bad luck, it’s hard to say. In any case, the surgery would cost him nearly all of 2010. He wouldn’t return to the mound in a regular season game until the final few weeks of the 2011 season, when he made five appearances in the Arizona Rookie League.

To keep his innings down coming off of the surgery, the A’s moved Leon back into a bullpen role for the 2012 campaign. He began the year with High-A Stockton but moved up three levels in that season. He would spend the bulk of the year in Triple-A. All told, Leon posted a 2.70 ERA and a 74:23 K:BB in 66.2 relief innings in 2012. That off-season, the A’s protected Leon from the Rule 5 draft by adding him to the 40-man roster.

In 2013, Leon finally made a permanent return to the starting rotation. Before the regular season got underway, Leon had an odd spring training. He pitched for Team Mexico in the World Baseball Classic and was the pitcher who hit Canada’s Rene Tosoni, touching off an epic brawl that made highlight reels around the world. The incident had no carryover for Leon during the regular season, however. He split the year between Double-A and Triple-A, throwing a career-high 144 innings in the process. Leon didn’t have his swing-and-miss stuff in 2013, but he was efficient, getting groundball outs early in counts. He averaged nearly six innings an outing and his control was excellent. He walked just 24 and struck-out 97. Leon also allowed just 13 homeruns.

Last season, Leon spent the entire year – save one day – in the A’s Triple-A starting rotation. He was recalled to Oakland in early May when the A’s thought they might need him in the bullpen as part of a doubleheader caused by an early-season rainout. The A’s didn’t end up needing to use Leon in that game, and he was sent back to the minors that night. The rest of the season, he pitched in Triple-A and made 27 starts. He tossed a career-high 145 innings and had a 4.97 ERA. His K-rate jumped up significantly (15.8% in 2013 to 20% in 2014), although his BB-rate doubled (3.9% to 8%). Still, his K:BB was a solid 2.51. Leon had a 41.5% groundball rate and he allowed 12 homeruns. He pitched better than his ERA would indicate, checking in with a 2.69 FIP.

Leon’s season didn’t end with the close of the 2014 MiLB regular season, however. Over the past three months, Leon has been arguably the best starting pitcher in the Mexican Winter League. In 10 starts, Leon has a 2.05 ERA for Culiacan. Leon has dominated the MWL with only 37 hits allowed and 59 strike-outs in 57 innings. He has walked just 12 and has allowed five homeruns. Leon has reportedly had his fastball clocked as high as 96 MPH during his MWL season. Over his last seven starts, he has allowed three hits or fewer and two runs or fewer in 37.1 innings.

Former A’s minor league pitching coordinator and current bullpen coach Scott Emerson calls Leon "probably one of the organization’s hardest workers."

"Anytime you can give Arnold the baseball and watch him pitch, it is fun to watch," Emerson said. "He's an aggressive pitcher with four pitches and he uses both sides of the plate. He's maturing each and every outing as a starter."

Now more than four years removed from Tommy John surgery, Leon may finally be reaching his full potential in terms of the maturation of his pitches. His fastball has generally sat 89-92 MPH, but, if the reports from Mexico hold true, he could be pitching with even better velocity in 2015. He has been clocked in the US in the past at 95-96 as a reliever. Leon also has an excellent change-up and a big, bending curveball that he can throw for strikes. Leon’s command has always been a strength and he is aggressive against both right-handers and left-handers.

Leon will be in his final option year in 2015, so if the A’s want to get a look at him in the big leagues before he is out of options, they will need to do so this year. Leon has plenty of experience as both a starter and a reliever and could play a swingman role for the A’s much like Jesse Chavez and Drew Pomeranz have over the past two seasons. The A’s have added plenty of upper-level starting pitching with their off-season trades, but Leon should be in the mix to compete for a spot on the A’s staff this spring. He won’t be a favorite to break camp with the A’s, but if he comes into spring training throwing like he has this winter, he could be a surprise addition to the 25-man roster. Leon will be 26 until early September.


Oakland Clubhouse Top Stories