SEATTLE -- Among the large group of Mariners prospects invited to Summer Camp, the youngest is 18-year-old shortstop Noelvi Marte. But while he’s yet to even play professionally in the United States, the teenager from the Dominican Republic already physically looks the part of a big leaguer.

Maybe it’s the gold chain dangling from his neck, or the broad shoulders and already filled-out frame. Either way, Marte gives off an imposing air for one so young.

Though still listed at his initial signing size of 6-foot-1, 181 pounds, Marte has filled out considerably since then and looms large even among his older teammates while displaying impressive power in his first batting practice sessions at the expansive T-Mobile Park.

Marte was one of the top international free agents in 2018, when he signed with Seattle for a $1.55 million bonus, and is already ranked as Seattle’s No. 6 prospect, per MLB Pipeline. He backed that up by hitting .309/.371/.511 with nine homers and 54 RBIs in 65 games for the Mariners’ Dominican Summer League team last year.

Though he’s yet to even begin his Minor League ascent, the Mariners included him among the 60 players invited to Summer Camp and will get him as much experience as possible this year, working with the extra group of players who will shift to Tacoma’s Cheney Stadium once the regular season begins on July 24.

“I can certainly see why our scouts and player development people are so excited about him,” said Mariners manager Scott Servais. “You just look at the physical attributes that he brings. … He’s fun to watch and is going to be an interesting player to follow as his career continues to move up the ladder because the tools are real, there’s no doubt about that.”

Marte is working in the afternoon sessions the first week of camp, taking ground balls with starting shortstop J.P. Crawford during infield drills and soaking up as much as possible.

“He's got a lot to learn, and he’s wide-eyed every day,” Servais said. “I think it's great he's paired up with J.P. Crawford. J.P is really fundamentally sound. Marte’s got a ton of talent, but he needs experience -- and sometimes the great players, they just watch other players and how they're doing and how easy they make it look.

“I’m really impressed with what I’ve seen there, but again, he’s 18 years old. This camp is really, really valuable for those young players, so I'm excited to have them here. I think it's great that we brought everybody in. We’re exposing them to where they ultimately want to get to, but around players that have been there and put the work in.”

Second baseman Shed Long, just beginning his own Major League career at age 24, has worked with Marte in the afternoon sessions as well and is among the impressed.

“He’s amazing,” Long said. “He’s huge, and 18? I told him he was 28. He’s got all the tools, and I think he’s going to be a good big league player. He’s got to get older, but he’s definitely matured way quicker than a lot of guys. I’m excited to see what he brings to the table, for sure.”