PEORIA, Ariz. -- Though they represent the future for the Mariners, a number of the club’s premier young prospects were among the eight players cut from Major League camp on Monday as the roster continued being whittled down for the impending season-opening trip to Japan.

Justus Sheffield, ranked by MLB Pipeline as the Mariners' No. 1 prospect, was among the cuts despite a strong camp in which he established himself as a candidate for the rotation when needed.

Also sent to Minor League camp were right-hander Justin Dunn (the club's No. 3 prospect), first baseman Evan White (No. 4), outfielder Kyle Lewis (No. 7), right-hander Erik Swanson (No. 9) and second baseman Shed Long (No. 12).

The two other players reassigned were catcher Joe DeCarlo and right-hander Jorgan Cavanerio.

The moves leave 44 players in big league camp with just three more days until the club flies to Tokyo on Thursday. The plan is to bring 30 players to Japan, though only 28 will be on the active roster that must be announced by the morning of the opener against the A’s on March 20.

Sheffield, Dunn, Swanson and Long all were acquired in the offseason as general manager Jerry Dipoto overhauled the club and began reloading for the future. Sheffield and Swanson came from the Yankees in the James Paxton trade, and both appear close to Major League-ready as they head to Triple-A Tacoma.

Dunn came from the Mets as one of five players acquired for Robinson Cano and Edwin Diaz. He’s expected to open the season in Double-A Arkansas.

Long, acquired from the Reds as part of a three-way deal with the Yankees for outfielder Josh Stowers, was one of the early standouts in camp and will continue to be worked at multiple positions in order to increase his options.

Lewis and White were Seattle’s first-round Draft picks in 2016 and ’17, and both were in their first Major League camps. Lewis might have been the best story among the young prospects, hitting .389 with a pair of home runs in 18 Cactus League at-bats and finally fully healthy after missing the past two springs following knee surgeries.

White also showed well before injuring his hamstring about 10 days ago. He’s back at full speed now and is expected to begin the season along with Lewis at Arkansas.

LeBlanc’s start delayed

With rain threatening Monday’s Cactus League outing against the Royals, the Mariners decided to scratch starter Wade LeBlanc and went with seven relievers in the 5-1 loss.

Servais didn’t want LeBlanc to start and then have to stop before getting all his work in, so the veteran lefty will pitch instead in an intrasquad game on Tuesday afternoon at the Peoria Sports Complex.

Shawn Armstrong got the start and gave up four hits and two runs in his inning. Dan Altavilla allowed back-to-back homers in the third, but the rest of the staff allowed just one more run, including a pair of shutout frames with one hit by Rule 5 Draft pickup Brandon Brennan.

Injury updates

• Though rookie reliever Gerson Bautista appeared to be seriously injured when he clutched his right chest and shoulder after delivering a pitch in Sunday’s split-squad game against the Angels in Tempe, manager Scott Servais said the hard-throwing right-hander may have just suffered a cramp in his pectoral muscle and hasn’t been ruled out of making the trip to Japan.

“He’s going to have to be able to pitch in a game before he would head to Japan,” said Servais, whose team has only two remaining Cactus League contests before flying to Tokyo on Thursday. “He’s had a great spring. I think he’s going to help us a lot this year. He just may not be available the first two games.”

• Veteran closer candidate Hunter Strickland is another who is fighting the clock to get ready for Japan. Strickland hasn’t pitched since March 3 due to a sore lower back, but he was slated to play catch on Monday in the hope he could be ready for a game on Tuesday or Wednesday.

“He’s another one that I really want to see in a game here and then get him in an exhibition [in Tokyo] and then have him available for the Oakland series,” Servais said. “But we’ll see.”

• Center fielder Mallex Smith took batting practice for the first time on Monday as he begins working back from the strained elbow that sidelined him from the start of camp.

Up next

Yusei Kikuchi will make his final Cactus League start in Tuesday’s 1:05 p.m. PT game against the White Sox at Camelback Ranch in Glendale. The Japanese free-agent acquisition will then make his MLB debut on March 21 against the A’s in Tokyo in the second game of the Opening Series.