Scouting Rangers Prospect #50: Ruben Sierra

The Texas Rangers selected outfielder Ruben Sierra, Jr. in the sixth round of last summer's MLB Draft because of his incredible raw talent. Lone Star Dugout takes a look at the 18-year-old outfielder with a feature article and an in-depth scouting report.

Vital Statistics:
Name: Ruben Sierra
Position: Outfield
DOB: March 10, 1991
Height: 6'2"
Weight: 172
Bats: Left
Throws: Left
Acquired: 2009 Amateur Draft, 6th round

When professional teams scouted Ruben Sierra, Jr. during his high school career in Puerto Rico, they saw a player loaded with undeveloped tools. While Sierra had potential, he also had a long way to go.

That raw talent enticed the Rangers to draft Sierra in the sixth round of last summer's draft, and they signed him for a slot-level $125,000 bonus just about two weeks after the draft.

From the get-go, Sierra's performance didn't induce much surprise out of Rangers brass or observers. He showed five-tool potential, but he also had all sorts of troubles against professional pitching. In 109 total at-bats, Sierra batted just .202 with three doubles while drawing eight walks and fanning 47 times.

One of the primary issues behind Sierra's struggles was his timing. He was having trouble catching up to above-average fastballs. Luckily, he began to make some adjustments.

His father, who was inducted into the Texas Rangers Hall of Fame during the 2009 season, visited Ruben Jr. approximately halfway through the Arizona League season to help with his swing.

"His dad came down for a couple of days, and they really worked on stuff they worked on when he was a young kid," said AZL Rangers hitting coach Jason Hart. "It helped us–our coaching staff–out. It gave us things to look for with him."

By the end of the AZL season, Sierra begin to look a lot like his father mechanically, from the batting stance, high leg kick, and swing.

Even after the summer, the Rangers' developmental staff still felt there was room for improvement with Sierra's swing. Although he was beginning to develop, Rangers Instructional League manager Jayce Tingler said his swing was still long and his timing was still a bit slow.

"The first day I saw him, he had a huge, huge leg kick," said Tingler. "The swing was a little long. I think the hitting coaches really did a good job of controlling the leg kick–not taking it away from him, but controlling it so his head is still and he was able to be more athletic. He was seeing the ball a lot better at the plate."

The adjustments clearly produced immediate results. Sierra turned in a strong performance at instructs, as he consistently hit line drives to all fields against elite pitching talent. The 18-year-old finished instructs among the leaders in the hitters' points system, which rewards things like base hits, walks, and effective situational hitting.

Tingler believes it's a major credit to Sierra that he was willing to make the changes so early in his professional career.

"I think Ruben was able to take a step back," he said. "It was very clear what he was there to work on on the offensive side, and the results didn't matter. He was able to just take his approach and what happened was he was seeing the ball well. The hits came because he was able to make those adjustments without putting pressure on himself."

Sierra may not put up outstanding numbers in 2010, and they may not even come in 2011. The outfielder will need a year or two of development before he can catch up to the game, but his high ceiling cannot be denied.

Jason Hart says it's only a matter of time before Sierra figures it out.

"He just has to get his man strength," Hart said. "He's got to mature and get a little stronger. He can run like the wind. His defense is improving every day. I think, if he sticks with it and keeps working hard, especially in the weight room, he's going to do fine."

Sierra is currently spending his first offseason with the Caguas Criollos in the Puerto Rican Winter League. Because Sierra is in his first season, he hasn't gotten any playing time, but he is working out with the club.

The prospect plans on returning to Florida in late-January, where he will work out with his father and further prepare for the 2010 campaign.

Also See: Seven teams, seven sleepers (November 13, 2009)
Lone Star Dugout Q&A: Jayce Tingler (October 26, 2009)
Rangers Instructs Report (October 8, 2009)
Sizing up the outfield prospects (October 1, 2009)
Lone Star Dugout Q&A: Jason Hart (August 15, 2009)

Batting and Power: Sierra has always enticed scouts with his outstanding physical tools, and that includes his offensive potential. The outfielder flashes raw power with a leg kick and a swing that bears a striking resemblance to his father's. Despite his impressive tools, Sierra built up a reputation out of high school in Puerto Rico as a raw player who struggled against live pitching.

Sierra certainly had his struggles with the AZL Rangers last summer, but he made gradual improvement as the season progressed. He took off in Fall Instructional League as the Rangers continued to work with him to tone down the leg kick a bit and improve his timing. The adjustments resulted in Sierra making not only more consistent contact, but also much harder contact.

The Puerto Rico native may need another two seasons before the results catch up to his talent, but he has proven to be coachable thus far and he has some of the most promising talent in the entire system. Even if Sierra has another ‘disappointing' year statistically in 2010, it will be far too soon to give up on him. Sierra's next couple of seasons are far more about the development than the production.

Base Running and Speed: The 18-year-old possesses excellent speed, but he still must learn about many of the nuances of baserunning in professional ball. His rather slender 6-foot-2, 172-pound frame will fill out as he matures and gets further into the Rangers' strength training program, and that will likely cause him to lose a step or two. Still, Sierra will probably always be at least a tick above-average in the speed department.

Defense: Sierra's defensive potential is off the charts, but like most other aspects of his game, the incredible talent is largely raw and undeveloped. The left-hander's excellent speed allows him to cover plenty of ground in the outfield, but he often had trouble reading balls off the bat last summer. Sierra has the tools to play centerfield, but his plus arm strength also lets him play in both corner spots. Sierra split time between all three outfield positions with the AZL Rangers in '09. As his body develops, he may lose a step or two, but the reads and throwing accuracy [and possibly arm strength] should only improve. Because of that, Sierra will most likely wind up in right field down the line, but he should always have the athleticism to fill in at all three spots.

Projection: Simply put, Sierra has one of the highest ceilings in the Rangers' system because of his five-tool potential, but only time will tell whether he can get anywhere near that ceiling. Sierra was regarded as a raw player out of high school in Puerto Rico, and that proved to be true during his debut summer with the AZL Rangers. On the bright side, Sierra appeared to be coachable in '09, making a handful of helpful adjustments at the plate. Like many raw-but-high-ceiling talents, Sierra may be one of those boom-or-bust prospects, but his talent makes him enticing.

2010 Outlook: The prospect would likely benefit from repeating the rookie-level Arizona League in 2010, and that's what will likely happen. At this point, Sierra just needs more repetitions and experience while his body fills out and his overall game develops. If he performs well with the AZL Rangers next season, he could get a late-summer crack at short-season Spokane.

ETA: 2014.

Year Team AVG AB 2B HR RBI R SB BB SO OBP SLG
2009 AZL Rangers (RK) .202 109 3 0 10 14 7 8 47 .254 .229

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