PEORIA, Ariz. -- The Mariners whittled their roster down to 36 players on Sunday as infielder Shawn O'Malley and right-handers Joe Wieland, Casey Coleman and Justin De Fratus were sent down with one week remaining in camp.
O'Malley and Wieland are on the 40-man roster, so they were optioned to Triple-A Tacoma. Coleman and De Fratus, as non-roster invitees, were reassigned to Minor League camp.
The O'Malley move leaves Luis Sardinas and Chris Taylor as the two remaining candidates for the utility infield role. O'Malley, 28, played well as a September callup last year and batted .471 in 34 Cactus League at-bats this spring, but the Mariners feel he's not quite as good defensively at shortstop as Sardinas and Taylor and view that as a critical need for their current utility situation.
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"He played great and really had a good camp," manager Scott Servais said. "What he can do as an offensive weapon -- he gets on base, switch-hits, he's versatile throughout the outfield and infield. The one thing we talked to Shawn about is trying to get him more time at shortstop.
"That's the one position he's probably not quite at the same level as some of the other guys at this time, we feel. That doesn't mean he can't get there. He's gotten a lot better in the last couple years. I saw him a couple years ago in Anaheim when we had him, and I think he's really improved his game."
Servais said Wieland, who was acquired by trade from the Dodgers in January, will work as a starter in Tacoma, while Coleman and De Fratus are headed for the Rainiers bullpen.

Wieland, 26, had a 6.55 ERA in 11 innings this spring. He made two starts for the Dodgers last year and was 10-5 with a 4.59 ERA in 22 outings for Triple-A Oklahoma City as he continued working back from Tommy John surgery in 2013.
"He had one outing where he lost his curveball for four or five pitches when he needed it," Servais said. "But I think he'd be an excellent guy to be able to call on at any point. Just getting through a season with five or even six starters is really tough, so I'd feel very confident if we needed to go get him that he could give us a good start or multiple starts in the big leagues.
"He's at that point in his career where he's now healthy and I trust him. We drafted him when I was with Texas, and I like his makeup and how he goes about things."
The Mariners still have position battles playing out for their final rotation spot, the final spots in the bullpen, backup catcher and first base as well as the utility role.
Seven outfielders are still in camp competing for five spots: Norichika Aoki, Leonys Martin, Seth Smith, Franklin Gutierrez, Nelson Cruz, Stefen Romero and Daniel Robertson.
Remaining infielders are Adam Lind, Robinson Cano, Ketel Marte, Kyle Seager, Sardinas, Taylor and backup first-base candidates Dae-Ho Lee, Efren Navarro and Jesus Montero.
Montero's situation appears in flux, however. The 26-year-old is out of Minor League options and left the complex on Saturday after clearing out his locker, most likely waiting to see if he clears waivers. The team has made no announcement on his situation and Servais said he was spending Sunday "with his family."
Lee had a Sunday opt-out in his contract, but he was added to the 40-man roster prior to the afternoon's game against the Cubs.
The catching competition apparently will go down to the wire, with left-handed-hitting Rob Brantly and Steve Clevenger battling for the backup spot behind starter Chris Iannetta.
Starting pitchers still in camp are Felix Hernandez, Hisashi Iwakuma, Wade Miley, Taijuan Walker, Nathan Karns and James Paxton, with the latter two competing for the fifth spot.
The bullpen has right-handers Steve Cishek, Joaquin Benoit, Tony Zych and Mayckol Guaipe, along with non-roster invitees Joel Peralta, Donn Roach, Blake Parker and Justin De Fratus, plus left-handers Vidal Nuno and Mike Montgomery. Relievers Charlie Furbush and Evan Scribner are also still in camp, though both are dealing with injuries and won't be ready for Opening Day.
The 25-man roster has to be finalized by next Sunday, prior to the season opener on April 4 in Texas.