Update 12:05 p.m.: The Mariners have placed starting pitcher Wade Miley on the 15-day disabled list with a left shoulder impingement and designated reliever Steve Johnson for assignment. Relief pitchers Jonathan Aro and David Rollins have been recalled from Triple-A Tacoma to take their place on the roster.

BOSTON – While nothing has yet to be officially announced, the Mariners are expected to add Adrian Sampson to the team in Boston.

Sampson, 24, has led the Tacoma Rainiers starting staff this season with a 3.25 ERA in 13 starts while striking out 61 and walking just 12. In his last start for the Rainiers he pitched six innings and gave up no runs.

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Sampson will likely be officially promoted after Friday’s game to take the place of the injured Wade Miley as Saturday’s starter.

Other than three appearances out of the pen early in his minor-league career, Sampson has pitched exclusively as a starter. He may be coming up to fill a long role in the pen that was taxed in the Rays series, or he could be coming up to make a start with another bullpen move also coming. We will find out later in the day.

Sampson is not on the Mariners’ 40-man roster. One option to get him on the roster could be to transfer Tony Zych, who was placed on the 15-day DL retroactive to May 2, to the 60-day DL.

A native of Redmond who graduated from Skyline High School, Sampson was acquired last year from Pittsburgh in the J.A. Happ trade.