Most Instriguing Prospects at Instructional League

Instructional League, held at the St. Louis Cardinals training facility in Jupiter, Fla. from late September to early October, can represent a turning point in a prospect’s career. It’s a time when a handful of chosen players convene in a spring-training-like environment to practice all the little things farm director Gary LaRocque and his staff think they need to work on. It’s also when coaches get their mitts on newly drafted players, who are generally left alone in their debut seasons to show what they can do.

Now that this year’s Instructional League is over, we take a look at the players who stand to benefit the most from what they just learned and practiced in Florida.

Magneuris Sierra, OF (Johnson City/Peoria)

Credit: Bret Jacomet/Johnson City Cardinals

Signed out the Dominican Republic in 2012 for a mere $105,000, Sierra may go down in Cardinals lore as the organization’s best Latin signing ever. Hyperbole perhaps, but the 19-year-old outfielder has the goods. In 2014, his first in the States, he led the Gulf Coast League in hits (78) and batting average (.386), and the Cardinals named him the Minor League Player of the Year.

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The late Oscar Taveras is the only other graduate of the Cardinals’ Dominican Academy to do that, and Sierra seems to be on a similar developmental path. Sierra sprays the ball to all fields and has more discipline than most other players his age. He also has better wheels than Taveras did, which is why Sierra profiles as a centerfielder.

Then again, his rocket arm means he could be a nice fit in rightfield, too. If he can adjust his flat swing to get some loft on the ball, he could blossom into a power hitting corner outfielder. He’s already shown he can handle adversity. The Cardinals were encouraged enough by his breakout 2014 to start Sierra in low-A Peoria this year, but he struggled against pitchers who could consistently locate their breaking balls.

On June 9, hitting just .179, the Cards sent him to rookie-level Johnson City, where he got his groove back (.315 BA and .371 OBP) and was named an Appalachian League All-Star. So relax, Cardinal Nation. Sierra is back on track and learning to hit those breaking balls with authority at instructs this fall.

Edmundo Sosa, SS (Johnson City)

Credit: Bret Jacomet/Johnson City Cardinals

2012 was a very good year for the Cardinals on the international market. Not only did they land Sierra. They got top overall prospect Alex Reyes and Sosa, too. And like Sierra, Sosa’s calling card so far has been an advanced plate approach. He’s shown he can use the whole field and has the patience to wait for good pitches to hit. Young, 19-year-old just don’t do that, and the Cards have two of them.

Sosa joined Sierra in Johnson City this summer, and the former hit .300 while playing solid defense at short. The issue with Sosa is his speed. He’s got it. He just doesn’t use it well on the basepaths. The 5-11, 170-lb. Panamanian has stolen 21 bases in his three seasons in the system, but he’s also been caught 12 times. Not only does he need to run more, he needs to learn how to read pitchers so he can get better jumps. Guess what kind of drills he’s doing a lot of in Jupiter right now?

Carson Kelly, C (Palm Beach)

Credit: Steve Mitchell-USA TODAY Sports

Instructional league has been important to Kelly’s career. Back in 2013, the Cardinals used it to begin Kelly’s conversion from third baseman to catcher. Whatever they did worked, because two years on Kelly is the best catching prospect in the system. Pitchers like throwing to him, he has a good ability to block pitches in the dirt and plenty of arm to already be about league average in terms of throwing out base stealers.

The problem is the bat. He hit just .219 at high-A Palm Beach this summer, and you could chalk that up to him focusing on catching. But he has yet to hit better than .257 in his four years in the system. The reason used to be the vast number of ground balls he hit, but for the last two seasons he’s hit about as many balls in the air as on the ground. With good bat speed, Kelly’s hit tool should improve with age. We’ll see if the extra work he put in this fall made any difference.

Next: Breaking down the baby birds in the Arizona Fall League