SARASOTA, FLA. – Orioles right-hander Miguel Castro, who enters the Grapefruit League season as the leading candidate for the team’s fifth rotation spot, will not make his first scheduled spring start on Sunday because of patellar tendinitis in both knees.

Castro -- who sparkled last season as a multiple-inning reliever and is transitioning back to a starting role – was slated to start Sunday’s Grapefruit League game against the Boston Red Sox in Fort Myers. Right-hander Gabriel Ynoa will start that game in his place.

The 23-year-old Castro pitched 46 2/3 innings after the All-Star break, more than any big-league reliever in the second half. Encouraged by his success as a reliever, the Orioles committed to make Castro a starter – he began his pro career as a starter in the Blue Jays system – and initially there was a major need for him to do so. But after the signings of Andrew Cashner and Chris Tillman over the past week, Castro is now competing for a back-end rotation spot with Rule 5 pick Nestor Cortes Jr., Mike Wright Jr., Gabriel Ynoa and Rule 5 pick Jose Mesa.

Castro, who was listed at 6-foot-7, 205 pounds last season, said last week he was attempting to add additional weight onto his lean frame, saying he believed it would help him physically handle the grind of starting.

“I feel really good right now,” Castro said then through interpreter Ramon Alarcon. “I’m trying to gain a little more weight but right now I feel really good. … I think it will help me as a starter, get longer starts, allow me to go more innings this year.”

Castro went on the disabled list twice last season, including one time at the major league level for shoulder inflammation. During his first season with the Orioles, he posted a 3.53 ERA and allowed just 53 hits over 66 1/3 innings.

Farmhand suspended: Low-level minor leaguer Jaime Estrada has been suspended without pay for 50 games after testing positive for the banned stimulant Strychnine. The 22-year-old Estrada, a third baseman who was the Orioles’ 26th-round pick in 2016, spent the past two seasons playing for the Orioles’ Rookie-level Gulf Coast League team, hitting .246/.374/.310 with one homer and seven RBIs in 53 total games.

He is still on the GCL roster, so he will begin his suspension when the CGL season begins in June.

Around the horn: Orioles manager Buck Showalter said that recent additions Cashner and Tillman won’t pitch in Grapefruit League games before Tuesday. Both are working out and throwing bullpen sessions. Cashner threw his second pen session on Friday. … Showalter said he will let outfielder ColbyRasmus tell him when he’s ready to get into games. “Want him to get his feet on the ground for the next couple days, ask him and then tell him what my thoughts are,” Showalter said. “But most importantly, this guy is an eight- or nine-year veteran, he knows how to get ready. … I think he’s in a good place.” … The Orioles and all other MLB teams wore caps from the Marjory Stoneman Douglas baseball team for Friday’s game as a way to honor the victims of the school shooting there Feb. 14. Caps will be autographed, authenticated and auctioned on orioles.com/auctions with the proceeds benefiting the Broward Education Foundation. “It was important to the organization to do it,” Showalter said “… I wish we could do more. Most importantly, I wish we could make it not happen.”

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