Stearns will be reassigned to a pro scouting position once he returns, general manager Jack Zduriencik said. Zduriencik indicated the team will name its new Tacoma manager in several days.
Stearns, a four-time National League All-Star catcher during his playing days with the Mets, has been in the Mariners organization for the past four years. He originally was hired by the Mariners to work in their pro scouting department and was the Minor League catching coordinator in 2012 and the first part of last season before working briefly as Seattle's third-base coach before taking over as Tacoma's manager in May.
"It kills me because the thing we all want to do in this business is be in the big leagues," Stearns said. "I've got 20-some years in the big leagues and about 20 in the Minors. I want to come back at my age and have another shot, but I didn't want to do it at the expense of the players and the organization. I think I can get healthy, but it's going to be later on."
"The continuity issue here is the major factor," Zduriencik said. "We all feel bad for John. It's tough on him to do this, but it's his decision. He came forward and said he just didn't think it was the right thing."
Donnelly, 67, is a veteran of 27 years as a Major League coach, including 14 as a third-base coach. He coached third for the Pirates from 1993-95, the Marlins from 1997-98, the Rockies from 1999-2002, the Brewers from 2003-05 and the Dodgers in 2006-07.
"As we move forward, the most important thing is making sure John gets healthy and can be productive again," said manager Lloyd McClendon, who has long histories with both Stearns and Donnelly.
Donnelly was a coach with the Pirates when McClendon played in Pittsburgh from 1990-94.
"Rich brings a lot of expertise," McClendon said. "He's been a bench coach, he's an ex-catcher, he's managed. There's a lot of experience that comes along with Rich Donnelly, and he'll serve us well."
But McClendon said it was difficult seeing Stearns step down, knowing how much he wanted to be part of the staff this season. Stearns was a veteran catcher with the Mets when McClendon started his own playing career as a catcher with that organization, and he said they've been friends ever since.
"This is a tremendous guy with a tremendous track record," McClendon said. "I know this is tough for him. He's a very proud individual and a very tough guy, so it was tough for him to do this."