The Seattle Mariners are calling up right-hander Logan Gilbert, their top pitching prospect, and he's likely to start Thursday against the Cleveland Indians, sources told ESPN's Jeff Passan.

Gilbert is ranked as the No. 43 prospect in baseball, according to ESPN's Kiley McDaniel.

Seattle is also expected to call up touted outfield prospect Jarred Kelenic, the No. 6 pick in the 2018 amateur draft, on Thursday, sources told Passan.

Gilbert made his Triple-A debut for the Tacoma Rainiers on Friday. He allowed one run on four hits with no walks and five strikeouts in five innings of work.

Gilbert, the 14th pick in the 2018 draft, popped up in the Cape Cod League the summer before his draft year, working in the mid-90s with above-average stuff and starter command. During his sophomore season at Stetson, he was pitching deep into games, regularly well over 100 pitches, and his velocity was hovering in the low 90s with a less sharp breaking ball.

He profiles as a bulk-inning midrotation starter with solid average stuff and plus command, according to McDaniel.

The 18-18 Mariners, third in the AL West entering Wednesday, have had to lean heavily on their bullpen after injuries to Marco Gonzales (left forearm strain), James Paxton (season-ending Tommy John surgery) and Nick Margevicius (left shoulder inflammation). Seattle is down to four healthy members of its six-man rotation to start the season: Yusei Kikuchi, Justus Sheffield, Chris Flexen and Justin Dunn.