Final Report Card Grades for Boston Red Sox Prospects at the Arizona Fall League

The Boston Red Sox may be attracting the most attention for all of the hot-stove rumors they’re involved in right now, but several of their players deserve notice for their performances in the Arizona Fall League, too.

The 2014 AFL season may now be in the books, but as it does every year, the league gave us a chance to take a closer look at many exciting prospects and players recovering from injury who could fill out MLB rosters in relatively short order.

The Red Sox sent seven such players to their AFL affiliate, the Surprise Saguaros. With their season now over, it’s useful to examine how Boston’s top prospects fared in a league with a lot of talent disparity.

We’ll just keep this list to players who can reasonably be considered prospects, so with all due respect to Robby Scott and Madison Younginer, we won’t be tracking their progress here, though the 25-year-old Scott was named an AFL Rising Star per Jon Shestakofsky, the Red Sox's manager of media relations and baseball information.

Rusney Castillo, CF

Michael Dwyer/Associated Press

AFL Stats
36 AB, .278/.333/.361, 10 H, 3 BB, 6 K, 3 2B, 0 HR, 1 SB

Castillo was off to a hot start in the AFL before a thumb injury sidelined him, ultimately benching him for the duration of the season after his first eight games. As ESPNBoston.com’s Gordon Edes noted, Castillo has the same injury that once upon a time impacted both Kevin Youkilis and Dustin Pedroia, but he should recover with ample rest.

It’s unfortunate that Castillo didn’t get more of a chance to shake off some of the rust he accumulated by not playing for over a year, but it’s hard not to be encouraged by what he did in limited samples in Boston last season and in the AFL. He has obvious bat-to-ball skills, decent power and some speed, and he could be a down-the-order threat for the Red Sox next season.

We still don’t know how Castillo will fare over a full season in the majors, and we’re not sure if his speed will play up on the bases as it does in the field. Still, he looks the part of a first-division starter from our initial glimpses of his talent.

AFL Grade: Incomplete

Keith Couch, RHP

USA TODAY Sports

AFL Stats
7 GS, 29 IP, 5.59 ERA, 14 K, 6 BB, 1.55 WHIP, 2 HR

Outshined by names like Matt Barnes, Anthony Ranaudo, Henry Owens and Brian Johnson, Couch has never received any attention as a prospect. Even after a successful 2014 campaign in Double-A in which he held hitters to a 2.96 ERA in 100.1 innings, Couch is anonymous among Red Sox fans.

Couch doesn’t seem to receive much attention from scouts or analysts because his MiLB numbers belie his fairly pedestrian stuff, and we can see that reality in his AFL stats. Couch was hit hard in seven starts, giving up 39 hits in 29 innings and surrendering two homers after giving up just three all year in Portland.

Couch will probably continue his career as a starter in the minors in 2015, but if he’s to have a meaningful MLB future, it will probably come in the bullpen. Don’t let his AFL numbers discourage you too much; he’s still a potential big league arm.

AFL Grade: D

Sean Coyle, INF

Christian Petersen/Getty Images

AFL Stats
67 AB, .209/.303/.343, 14 H, 7 BB, 22 K, 4 2B, 1 HR, 5 SB

It’s hard to be too disappointed in Coyle given how strong his 2014 campaign was, but his AFL stint was fairly rough. The 22-year-old recorded just 14 hits in 19 games, and while he did walk seven times, his 22 strikeouts represent his penchant for swinging and missing.

The good news is that Coyle put his power/speed combo on display in the AFL, notching six extra-base hits and swiping five bags. He gets the most out of his tools, and that should get him to the major leagues even if he lacks supreme athleticism.

He’s most certainly a prospect who’s skirting the line between backup or second-division starter, though, and he’ll need better performances than what he put up in Arizona to convince the Red Sox or another team that he’s worthy of an everyday spot.

AFL Grade: C-

Aaron Kurcz, RHP

Kelly O'Connor, www.sittingstill.net

AFL Stats
10 G, 14 IP, 3.86 ERA, 15 K, 9 BB, 1.50 WHIP, 1 HR

Kurcz is still recovering from Tommy John surgery, so it’s natural that he’s going to be fighting his command. Walking nine batters in 14 innings isn’t great, but considering he had walked six through his first seven innings, he at least showed improvement as the AFL went on.

When we checked in on the Red Sox’s AFL participants about a month ago, here’s what I wrote about Kurcz:

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An undersized right-hander who can reach the mid-90s with his fastball, per SoxProspects.com, Kurcz is mildly interesting as a middle reliever prospect who could be on the precipice of a call-up to the majors with a decent 2015 campaign. He’ll need to prove his stuff works against more advanced hitters, though, and that his lack of size won’t prevent him from reaching his ceiling.

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That’s still true today, and it’s a good sign that this right-hander turned his rough AFL start into a solid AFL finish.

AFL Grade: B

Deven Marrero, SS

USA TODAY Sports

AFL Stats
58 AB, .328/.443/.414, 19 H, 11 BB, 19 K, 5 2B, 0 HR, 2 SB

With Xander Bogaerts entrenched at shortstop for the foreseeable future, Marrero is a natural fit as the subject of trade rumors. After all, the 24-year-old has had an up-and-down professional career at the plate, but he’s an excellent defender capable of manning short for an MLB team right now.

Marrero’s AFL stint won’t help to quell the rumors that other teams have interest in acquiring his services, as general manager Ben Cherington told the media. Marrero put on an impressive performance with the bat and the glove in Arizona. Yes, he struck out 19 times, but Marrero also displayed a patient approach, some extra-base ability and swiped two bags.

It’s still unclear as to whether Marrero’s future lies as a utility infielder or a second-division starter, but performances like this will help convince evaluators that he’s closer to the latter. Look for Marrero to improve his offense at Triple-A next season.

AFL Grade: A-