Carter Kieboom knew he belonged.
A standout at Walton High School in Marietta, Georgia, the infielder had been invited to play showcases across the country in the summer of 2015 and passed test after test. He was named American MVP after going 2-for-3 with hits off future No. 4 overall pick Riley Pint and third-rounder Jesus Luzardo at Wrigley Field. The following May, he helped Walton win a state title, scoring the winning run in a walk-off victory over Pope, who used future No. 13 overall pick Josh Lowe on the mound in the final frame.
But it was during those trips across the country that Kieboom really started to sense he could hold his own against the best, and he carried the voice of his brother Spencer, a catcher in the Nationals' system, as he went.
"Spencer told me to stick to what got me there," he said. "So I didn't watch anybody or try to pick anything up. It was cool to see everyone there because you realize there's a lot more talent in the country than you think, even coming from my area. It makes you focus and be grateful for what you have. ... But it was more about the fact that I felt comfortable there, that I deserved to be out there. That was the best part of my time at those events."
The Nationals took Kieboom with the 28th overall pick last June and signed him away from a commitment to Clemson for $2 million. Now in his first full season, Washington's No. 4 prospect is doing a lot more than just fitting in. The 19-year-old has a .339/.405/.596 line with six homers, 10 doubles and 20 RBIs in 28 games for Class A Hagerstown. His 1.001 OPS and 183 wRC+ both rank third in the South Atlantic League.
There have been few, if any, growing pains in his introduction to full-season pro ball, something he could sense would happen during his first Spring Training at the Nationals' new facility in West Palm Beach earlier this year.
"Personally I knew I was going to belong there before I started the season," he said. "Just in Spring Training, playing with the guys, you have a sense of who the older guys are just based on how they play the game and their feel for the game. Even when they started dividing us for games, sometimes the low-A guys would play with the high-A guys, and even that was comfortable for me, I thought. I always knew I prepared the right way."
Video: Hagerstown's Kieboom clubs second homer
That preparation was done alongside his brother Spencer as well as Major Leaguers Charlie Blackmon, Josh Rutledge and Brandon Beachy, among others, back in Kennesaw, Georgia. While most high-school players trudge through their first offseason trying to follow their organization's guide to becoming a big leaguer, Kieboom learned first-hand from the genuine articles.
"I was fortunate to be around those types of professionals every day down here," he said. "When you're in that situation, you don't really talk. You just sit back and look at them go about their business and try to take in what's made them get to where they are."
All that prep dating back to high school, all the offseason showcases and a stint at Spring Training have allowed Kieboom to hit the ground running even faster than most expected. The 6-foot-2, 190-pound shortstop was expected to be an above-average hitter, though it wouldn't have been a surprise for him to need time to acclimate to Class A arms. He showed that might be the case last season, when he hit .244 with a solid .774 OPS but a rough 27.7 percent strikeout rate over 36 games in the Gulf Coast League.
Instead, Kieboom has gone above those expectations with the most surprising tool being his power. There seemed a chance that the right-handed hitter could grow into some decent pop as he matured physically, but he's already accelerating that timeline. He clubbed three homers in one game on April 30 and is tied for third in the Sally League with six long balls in 28 games. What's more, his .257 isolated slugging percentage ranks fourth in the circuit. These are not power numbers put up by a singles-only shortstop or even just an aim-for-the-gaps middle infielder.
"Power comes along with good swings," he said. "You've got to have confidence and patience. I think I've put together some successful at-bats. ... Nothing's really changed about my approach, other than knowing what to look for in certain counts. At this level, they're mostly throwing fastballs, so I try to be ready to swing early in the count. But I don't want to be overagressive because I was last year at times. I'm trying to slow things down and look for my pitch, and that's been working so far."
Video: Suns' Kieboom swats third homer
If Kieboom's offense continues to be better than advertised as the summer rolls along, his profile could skyrocket even more, assuming he can stick at shortstop. He played third base for a while in high school before moving over to the more demanding position, and given his size, a move back to the hot corner might make sense in the future. But MLB.com gave him an average grade for his fielding at shortstop this offseason, and Kieboom admits there's room to grow. (His .947 fielding percentage over the first month of 2017 is an improvement over the .932 he put up last year.)
"Ultimately, it comes down to comfort, and I feel like I've gotten really comfortable [at short]," Kieboom said. "There are different reads and judgments you have to make, and I've been working on my angles and my footwork, making those better every day. But I'd definitely say I've improved. I'm excited to get even better at short."
The Nationals' system took a hit this offseason when it dealt Lucas Giolito, Reynaldo Lopez and fellow 2016 first-rounder Dane Dunning, but if there's hope for the system to grow, it starts with Kieboom and his teammates in Hagerstown. He's combined with No. 3 prospect Juan Soto and No. 6 Sheldon Neuse to lead the Suns to the Sally League's best offense. Hagerstown hitters are tops in the circuit in runs, hits and all three slash-line categories, helping the club to a 19-14 record through Thursday.
"I couldn't be happier with the way things have started," he said. "I feel like I've adjusted nicely, and it's helped a lot to be alongside a great team. The chemistry we have already is a rarity at this level, I think. Really, everything is going the way I'd hoped."