The Orioles have designated Rule 5 righty Jose Mesa Jr. for assignment, per a club announcement. His roster spot will go to veteran starter Alex Cobb, whose four-year contract is now official.

Mesa, 24, was the last of three pitchers taken by the Baltimore organization in the most recent Rule 5 draft. Obtaining his rights in full from the Yankees would have required that the O’s carry him for all of the upcoming season on the active roster. Now, unless his Rule 5 rights are either traded for or claimed off waivers, Mesa will be offered back to the Yanks.

The young hurler obviously showed enough to draw interest from the Orioles after being left unprotected. In 84 innings at the High-A and Double-A levels last year, he allowed just 18 earned runs on 48 hits and 32 walks while recording 101 strikeouts. But it seems he’ll need some more seasoning before trying out the majors. Mesa struggled in his chances this spring, recording five strikeouts and seven walks in 7 2/3 innings.