Orioles reporter Jon Meoli discusses the injuries to Mark Trumbo and Ryan Mountcastle after their 1-0 win over the St. Louis Cardinals in Jupiter, Fla. (Jon Meoli, Baltimore Sun video)

Orioles prospect Ryan Mountcastle, who impressed with his power bat in his first major league spring training this year, will miss the start of the regular season with a hairline fracture in his right hand.

Manager Buck Showalter said Mountcastle, 21, will be out four-to-six weeks with a non-displaced fracture at the base of the fifth metacarpal in his right hand, which was suffered on a hit-by-pitch in a Triple-A game against the Minnesota Twins on Wednesday at the Buck O'Neil Complex at Twin Lakes Park in Sarasota. It will not require surgery, Showalter said.


Mountcastle was trying to pull his hands out on a pitch up-and-inside, but exposed his top hand and will be sidelined because of it. The minor league season starts April 5, and Mountcastle was ticketed to return to Double-A Bowie this season.

Showalter said the injury was "very similar" to what happened to shortstop J.J. Hardy last June, an injury that sidelined him for two months. Showalter said he had no indication the injury involved his hamate, a small bone in the hand that takes a long time to heal and can sap a hitter's power.

"He's got good young bones, and he'll be OK," Showalter said. "He won't miss that much."

Mountcastle was sent out from major league camp Monday with a .292 batting average and two home runs in 24 at-bats in the Grapefruit League. The youngest player in Orioles camp as a nonroster invitee, he was coming off a season in which he hit .287 with 18 home runs and 48 doubles between High-A Frederick and Bowie.

He led the minors with 51 extra-base hits at the time of his July 20 promotion to Bowie, where the organization moved him from shortstop to third base in an effort to help find him a permanent position where he can make his bat available at the major league level.

Mountcastle was the team's No. 2 prospect, according to Baseball America, who ranked him 71st on their league-wide Top 100 list.

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