Updated

New York Yankees right-hander Michael Pineda, who reported tightness behind his right shoulder after pitching on Friday, will begin the season on the disabled list with tendinitis, the team said on Saturday.

Pineda, who came to the Yankees in a trade with the Seattle Mariners after a standout rookie season, was diagnosed with the problem in his pitching shoulder after tests on Saturday and placed on the 15-day disabled list.

In Friday's spring training game against the Philadelphia Phillies, Pineda allowed six runs and seven hits in less than three innings of work.

The Yankees said they were relieved to find no structural damage for the big Dominican, who had been struggling all spring to regain the zip on his fastball.

"It's great news, for what your biggest concerns are," New York manager Joe Girardi told reporters at the Yankees' spring training camp in Tampa, Florida.

"It just needs a little rest. He'll get treatment and then we'll see how long until he picks up a ball. We'll be a little conservative."

Pineda, 23, was acquired from Seattle with hard-throwing minor league pitcher Jose Campos in a trade that sent New York's top hitting prospect, catcher/designated hitter Jesus Montero, and pitcher Hector Noesi to the Mariners.

The injury to Pineda ended speculation about New York's rotation to start the season.

Girardi said with Pineda unavailable, the order of starting pitchers would be CC Sabathia, Hiroki Kuroda, Phil Hughes, Ivan Nova and Freddy Garcia.

Last year, Pineda was 9-10 with a 3.74 earned run average, including an 8-6 record with a 3.03 ERA in 18 starts in the first half of the season.

(Reporting By Larry Fine in New York; Editing by Ken Ferris)