Arizona Fall League Preview: Mesa Solar Sox


Nov 2, 2013; Surprise, AZ, USA; Oakland Athletics shortstop

Addison Russell

against the West during the Fall Stars Game at Surprise Stadium. Mandatory Credit: Mark J. Rebilas-USA TODAY Sports

The Arizona Fall League kicks off in just two weeks as some of the best prospects from around baseball get set to square off in the annual six week circuit. Representatives of the thirty clubs are divided into six teams, and it’s difficult to find one with a wider array of talent than the Mesa Solar Sox, which will feature prospects from the Cubs, arguably the game’s best farm system, and from the Angels, arguably the game’s worst. In between, they’ll have delegates of the declining A’s system and the middling Nationals and Blue Jays ones. Here are the highlights:


Looking for a breakout prospect for 2015? Keep an eye on Mesa starter and Toronto representative Roberto Osuna. Signed out of the Mexican League three years ago, Osuna’s precocious stuff put him on the fringes of Jonathan Mayo’s top 100 prospect list each of the past two seasons. They graded his fastball, a lively pitch in the low to mid-90s, as an elusive 70 on the 20-80 scale, while also praising his slider and control as big league quality.

Ahead of the aging curve since he was a 16 year old pitching in the Mexican League in 2011, Osuna’s development was stunted by Tommy John Surgery last July.  It may prove only a small stumbling block, though. The right-hander returned on July 8th, little over a year after undergoing the procedure, and while he got strung up for a 6.55 ERA High-A Dunedin,he continued to miss bats, with 30 strikeouts in 22.0 innings. The AFL is the next step in his recovery, as Osuna will attempt to make up for lost innings and simultaneously prove he can dominate his prospect peers.

Also making up on lost time is Cubs starter C.J. Edwards. The scrimpy right-hander – he is listed at 6’2 and just 155 pounds – missed three months this season with a mysterious shoulder injury, granting credence to longstanding durability concerns that stem from his slender frame. Edwards’ stuff has never been questioned, nor his ability to translate that raw talent into tangible results (1.86 ERA across 237 innings). But his major league future will be contingent on his ability to simply stay on the mound. For Edwards, this October will be more about building up arm strength than anything else.

In the bullpen, Mark Sappington is the chief name to remember. After a disastrous few months as a starter this year, Anaheim converted the  23 year old right-hander to relief in July. He grasped the role quickly, posting a 3.38 ERA and a 13.8 SO/9 in 32.0 innings down the stretch for Double-A Inland Empire. The big league bullpen could beckon in 2015.

Position Players

Out of the Cubs’ sea of hitting prospects, only two will make the cross-country trip to Mesa: Addison Russell and Dan Vogelbach. Vogelbach is the lesser known name, though he is the more noticeable player around the diamond. The broad-chested first baseman stands two inches shorter than C.J. Edwards but is nearly 100 pounds heavier, creating a hulking frame Vogelbach can leverage into plus power to all fields. ranked him as the Cubs’ 10th overall prospect, noting that he manages grade 60 power without the swing and miss of most large sluggers.

Leaner and more athletic, Russell is ranked by as the 5th best prospect in all of baseball. He too missed significant time this season but was healthy and productive since coming over from the Athletics in the Jeff Samardzija trade, hitting .294/.332/.536 in 205 plate appearances for Double-A Tennessee. Last offseason, Billy Beane, his GM at the time, hinted the shortstop could make his major league debut in 2014. Injuries and this summer’s blockbuster prevented that, but Mesa could be one of the last opportunities to see Russell without paying big league ticket prices.

Russell may be Chicago property now, but Oakland has no shortages of representatives in the Mesa lineup. Daniel Robertson, their first round pick from 2012, is fresh off a career year for High-A stockton (.302/.401/.472), a year that put him on top of’s top 20 Athletics prospect list. To quote Mayo, “Robertson is not as electric as Russell (since traded to the Cubs) — few shortstops are — but Robertson profiles as a fine hitter who could stick in the middle infield.”

Stockton first baseman Matt Olson also earned a roster sport, and a well deserved one at that. The 21 year old led all of North American Professional Baseball with 117 walks. As big-name prospects Joey Gallo and Kris Bryant partied like it’s 1998, Olson quietly finished third for the minor league home run title, with 37. He has more power than any other player in Oakland’s system, as much as any other prospect in the Arizona Fall League.

For some, the Arizona Fall League is a stepping stone, for others, its the last jagged rock on the edge of a cliff. As recently as February of 2013,  third baseman Kaleb Cowart was considered by Baseball America to be the No. 1 prospect in the Angels’ system, the No. 60 in all of baseball. A first round pick out of high school, he had hit .276 with 16 home runs and an .810 OPS Between low and high-A as a 20 year old in 2012, and was lauded for his plus hit tool and outstanding infield arm.

Rarely has a prospect fallen so suddenly. Cowart posted a .279 on base percentage in 2013. He didn’t hit for power. He didn’t for average. His OPS fell .230 points from the year prior, and the formerly sure-footed defender committed 25 errors at the hot corner. Cowart looked atrocious, but that was just one bad year. Plenty of prospects go through them. Plenty come out on the other end.

Not Cowart. This year, his second in Double-A,  his average ticked up just 2 points to .223. He hit only 6 home runs for the second consecutive season. His OPS rose .39 points, but was still only .619. He committed another 23 errors. There’s still talent here, but it has to materialize, and fast. If he doesn’t hit this October, in the dry Arizona air, will he ever?