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Toolshed: Health a priority for Soto, Kieboom

Nats prospects' second attempts at full seasons could be special
Carter Kieboom and Juan Soto played a combined 71 games with Class A Hagerstown last season. (Patrick Cavey/MiLB.com)
March 16, 2018

WEST PALM BEACH, Florida -- A foundation for lasting success isn't built on success alone. Even the most talented prospects must find out firsthand what doesn't work before they can grow into successful Major Leaguers with long careers.By any measure, last season was supposed to be an important one for

WEST PALM BEACH, Florida -- A foundation for lasting success isn't built on success alone. Even the most talented prospects must find out firsthand what doesn't work before they can grow into successful Major Leaguers with long careers.
By any measure, last season was supposed to be an important one for Nationals prospects Juan Soto and Carter Kieboom. It was meant to be the first time either played 100-plus games in a Minor League season, starting with Class A Hagerstown, where they could show off the lauded offensive tools that made them top-100 prospects. That didn't happen as injuries limited Kieboom to 48 games in the South Atlantic League and Soto to 23. What they learned along the way, however, should provide building blocks for two players with big-time potential.

Soto, an outfielder ranked No. 2 in the system, was first to go down. Playing in what was meant to be his first full season at age 18, MLB.com's No. 29 prospect suffered a fractured ankle sliding into home on May 2. He wouldn't play for the Suns again. A rehab assignment in the Gulf Coast League in July ended after five games as Soto needed surgery to remove the hamate bone in his right hand. Another four-game set in the GCL came to a premature conclusion with a hamstring injury in early September.
It may have seemed a star-crossed season, but the Dominican standout is rolling with the education his health woes provided.
"It had its good and its bad, actually," he said through an interpreter. "It may have seemed bad on its surface, but because I learned so many things about my body, how to treat some of the injuries, how to prevent certain things, how to strengthen parts of my body that were weak, there was some good to it."

Part of the upside was continuing to hit everywhere he went. Soto produced a .360/.427/.523 line with three homers and five doubles in his 23 games for Hagerstown before the first injury. His strike-zone discipline was impressive for a teenager at a full-season level -- eight strikeouts and 10 walks in 96 plate appearances. This could easily be chalked up to small-sample craziness if Soto hadn't already been the GCL MVP in 2016 after hitting .361/.410/.550 in 45 games in a league not known for its offense.
Entering his third stateside season in 2018, Soto has worked to strengthen his ankles and wrists to make sure he doesn't see a repeat of 2017. But he's also focused on speed and defense to round out his profile. He wants to run and field just as well as he's hit, but to hear him break down the mechanics of his swing, it's not difficult to understand how a mature understanding of hitting has made him so consistent when he is on the field.
"I think it's my head," Soto said. "If my head swings a little too much, then it kind of sways my whole body off course. But if I can keep my head steady, it keeps my body aligned and in place and working well, and I have those better results."

The Nationals are watering at the mouth at the concept of seeing what their potential next star outfielder can do when able to play from April to September.
"Obviously, he's so advanced for his age," director of player development Mark Scialabba said. "He's calm in the box and has such confidence with everything he does. We're very happy with where he was offensively. To have success very early in his career shows what's he capable of. Hopefully he can grow even more in the future, but right now, he's a very special man of hand-eye coordination, power, strength in his swing. It's exciting to see him healthy and strong on the field this spring. He's somebody who has an impact bat and hopefully is a National for a long time."
Kieboom may have entered 2017 with a little less hype, but he still came into the season as the No. 28 overall pick in the previous Draft. The team's No. 3 prospect showed why quite quickly with Hagerstown, hitting safely in 10 of his first 11 games following Spring Training. The right-handed-slugging shortstop owned a .333/.398/.586 line with six homers, 10 doubles and 20 RBIs in 29 games through May 12, when he pulled up lame running to first base with a hamstring injury. He didn't return until Aug. 15 after rehab stints in the GCL and New York-Penn League.
Compared to Soto, Kieboom had a longer season, but he expressed similar thoughts looking back.
"It's definitely disappointing," Kieboom said. "It's just a bump in the road, though. Things happen. I know now that that's something I keep track of. I'm always working my hamstrings. For any part of your body, you always want to maintain it. I don't think it stepped me back from anything. With all that down time, I was still watching videos, still doing what I could. I don't think I missed a beat with it."
It helped that in those training sessions, the Georgia native had plenty of positives to fall back on from his early days in Hagerstown. His power translated quickly to a full-season affiliate, and the replays he was studying he knew were of the good times. When it was time to get back in the cage, he already could see the blueprint laid out for him by his own work in April and May. He totaled 48 games with the Suns, and while his numbers weren't quite as rosy after his comeback (.235 average, .755 OPS, two homers in 19 games), he showed little difficulty understanding Sally League pitchers, compiling more walks (18) than strikeouts (15).
In that time, he also worked with training staff to better understand why the injury happened and what he could do to stop it from happening in the future.
"There are tons of things," Kieboom said. "If your body is weak in any one point, it tries to compensate with something else. I don't know what it was exactly, but my hamstring decided to take the brunt of something that was weak at the time or tired or whatever it may have been. It's not just stretching. You've got to make sure you're mobile in your hips, for example, so your hamstring isn't taking the full force."
Disappointed the team couldn't see more of Kieboom in 2017, Scialabba said he showed growth in all facets, on and off the field.
"Short sample early on, but he really established himself as someone who could be a run-producer for us and took his skills from spring and transferred them to the season," Scialabba said of MLB.com's No. 90 prospect. "He had some hiccups defensively, but that's normal from a young shortstop. He was getting really hot and just got hurt at the wrong time. He was controlling the strike zone well, showed power to all fields, could really barrel the ball consistently. It was just unfortunate, but he did a really good job of working his legs, rehabbing and then at the end of the season getting healthy and back in games in the season and instructional league. We were happy with where he finished."

If healthy, and that remains a big if, they are in an organization that has shown a willingness to get aggressive with young talent. Top prospect Victor Robles played 100-plus games for the first time in his age-19 season in 2016 and finished his age-20 season in the Major Leagues. Soto seems the more likely of the two to be on a similar track, given that he's produced a .362 average and .953 OPS in his first two Minor League seasons, but it's not out of the question that Kieboom could show enough pop over the next 18 months to warrant a look in the second half of 2019.
An aggressive arrival time for both young studs could be big for the Nationals, who will need to rely on homegrown talent if Bryce Harper leaves via free agency next offseason and Anthony Rendon does so the year after that. Washington isn't going to get ahead of itself, though. 
"It's important that we establish that foundation early in their careers," Scialabba said. "The game gets fast as you move up. In Double-A, you could do well and get called up pretty quickly, as we saw last year with Victor. So we want to do everything we can to cover as many bases as possible at the lower levels."
That starts with health. Both Soto and Kieboom have done plenty to show that they're capable of big things in the Minors, but that alone doesn't make a professional baseball resume. Though Scialabba was non-committal about where either would begin in 2018, they are likely headed back to Hagerstown in order to broaden their base of South Atlantic League success. No matter where they begin or end the upcoming campaign, the pair has the exact same goals in mind.
"I think my goal is to just keep working hard this year, and for me, a good outcome is to make it a whole season and stay healthy," said Soto.
"Just to play a full season would be huge," Kieboom said. "I've yet to have my body go through a full 140-game season. Yeah, I'm down here [when I'm injured], but it's not the same as playing a game every day. Just the idea of playing 140 games is huge. Being there all year, being around the guys all year would be great. The best player is a healthy player."

Sam Dykstra is a reporter for MiLB.com. Follow and interact with him on Twitter, @SamDykstraMiLB.