© 2014 MLB Advanced Media, L.P. All rights reserved.

4/16/2014 5:59 P.M. ET

Walker, Beavan both shut down

ARLINGTON -- With fill-in starter Blake Beavan going on the 15-day disabled list with right shoulder tendinitis and top prospect Taijuan Walker shut down for at least two weeks after tests showed a "shoulder impingement" on Wednesday, the Mariners are searching again for a starter for Sunday's upcoming Interleague Series finale at Miami.

Beavan started in place of injured left-hander James Paxton on Tuesday, but lasted just four innings in a 5-0 loss to the Rangers after his shoulder wouldn't loosen up in a 63-pitch outing.

Walker, the No. 6 rated prospect in baseball by MLB.com, was a consideration to return from his own shoulder issues by Sunday, but he had his own rehab start with Triple-A Tacoma wiped out Tuesday when his shoulder felt tight before he even began throwing.

General manager Jack Zduriencik said Walker had an MRI on Wednesday in Seattle that showed the impingement.

"We're going to back him off for two weeks and treat it and eventually work him back to the mound and start the progression again," Zduriencik said.

Walker was slowed at the start of spring by shoulder soreness and was shut down completely for a week in early March before working his way back through a pair of Minor League rehab starts.

"I think it is the same general area," Zduriencik said. "He just wasn't comfortable. So we sent him for tests and now we'll back him off and treat it and see where we're at."

The Mariners have been hit with a series of pitching issues, with Danny Hultzen, another premier prospect, already lost for the year following rotator cuff surgery and All-Star right-hander Hisashi Iwakuma still a couple of weeks from returning from a sprained tendon in his finger.

"It's amazing," Zduriencik said. "Everybody in baseball seems to be going through the same type of things, but ours is a little more severe than most. Nevertheless, this will give others an opportunity."

Among the current Tacoma pitchers, left-hander Anthony Fernandez, 23, is the one healthy starter who is on the Mariners' 40-man roster. Brandon Maurer is another possibility and he has Major League experience, but Maurer is just returning from back problems and hasn't pitched more than 3 1/3 innings this season.

Beavan also is going to be out at least two weeks, which is a frustrating situation for the 25-year-old right-hander after he'd just been recalled after Paxton strained his left oblique muscle in his third start of the year.

Beavan said he essentially has "dead arm" from a knot in his shoulder that isn't allowing him to throw freely.

"I just had no life on my ball," he said. "It's just frustrating because I had a great opportunity to help these guys and fill the void of other guys being down. Now I'm in the same situation, but hopefully it's something where in the next 10 days we can get out of there and slide back into the action and help us win some ballgames."

Beavan is flying back to Seattle on Thursday to begin rehab treatment with trainers in Seattle.

Mariners to make up game in Oakland on May 7

ARLINGTON -- The Mariners-A's game that was postponed on April 4 by poor field conditions in Oakland has been rescheduled as part of a doubleheader at O.co Coliseum on Wednesday, May 7, which is the final day of a three-game series in Oakland.

The two teams will play a 12:37 p.m. game, as originally scheduled, then play a second game 30 minutes after the first game concludes.

The doubleheader comes at the end of what now will be a three-city, 10-game road trip that begins in New York and Houston, with the Mariners then opening a seven-game homestand the following night at Safeco Field.

Seattle player representative Charlie Furbush said the Mariners pushed to have the game replayed in the middle day of the three-game series to avoid having a doubleheader on their getaway day.

"The first day was out of the question because they were flying back from Boston [the day before], so it would have been too quick of a turnaround," Furbush said.

The compromise was to hold a traditional doubleheader on the Wednesday getaway day instead of a split day-night twin bill, which would have made the second game later and had the Mariners flying home late at night with another game looming the next day.

"We'll survive," Furbush said. "We'll just have to go beat 'em twice."

Worth noting

• Until giving up 12 hits to the Rangers on Tuesday, the Mariners hadn't allowed double-digit hits in their first 12 games. That tied for the third-longest streak of fewer than 10 hits allowed to open a season over the last 100 years in the American League.

• Mariners closer Fernando Rodney has recorded 88 saves since 2012, the third most in baseball during that span.

Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.