Seattle left with roster challenges

SEATTLE -- The way he was pitching in the first inning of Tuesday's 10-4 loss to the White Sox, it looked like James Paxton was going to cruise through his five-inning threshold and duke it out with Lucas Giolito.

But Paxton left with one out in the second inning due to a left forearm strain, which all of a sudden creates enormous uncertainty for Seattle’s entire pitching staff. And another night against an overpowering starter, this time Lucas Giolito, proved to be another wakeup call for Seattle’s offense, which lost Jake Fraley to a hamstring strain in the fifth inning.

Basically, the Mariners left Tuesday’s game with more questions than answers about where they’re headed in the short- and long-term.

Where does the rotation go from here?

Nick Margevicius, who would be Paxton’s replacement in the rotation if it comes to that, relieved Big Maple on Monday and contributed 3 2/3 innings and gave up four runs, including homers to Zack Collins and Luis Robert.

The good: Margevicius proved to be stretched out by throwing 73 pitches and would be able to slot into the rotation.

The bad: Paxton has the best stuff of any pitcher on Seattle’s staff and his production will be difficult to replace.

Moving Margevicius to the rotation would also leave Seattle without an immediate reinforcement, should any of the other five starters have an issue. Among the rest of the arms on the 40-man roster, Ljay Newsome is the only clear starter. Former starter Erik Swanson could be stretched out, but he spent all of Spring Training gearing up for a bullpen role.

“Just off top my head, yeah, [Margevicius] probably would be, based on coming into Spring Training, our camp, and I thought he had a good camp,” manager Scott Servais said. “He was in competition with Justin Dunn. And as we've said all along, you need a lot of depth. These guys are all going to get a chance to pitch.”

How serious is Fraley’s hamstring strain?

Fraley suffered the injury while making a diving catch on a fly ball by Yoán Moncada in the fifth inning and will undergo an MRI on Wednesday. But he appears headed to the 10-day injured list, with Braden Bishop the most logical replacement given that he’s the lone outfielder left on the 40-man and is at the alternate training site.

Fraley entered Tuesday leading the Majors with eight walks, bringing his on-base percentage up to .588, a promising sign after an 0-for-15 start to Spring Training put his status for the Opening Day roster in doubt. Fraley broke camp, in part due to the absence of Kyle Lewis, who is recovering from a bone bruise in his right knee, and he’s started all five games thus far.

Bishop, who has a .128/.185/.151 slash line in 94 career plate appearances, is the most superior defender on the roster and would likely play center, which would move Taylor Trammell to left. The Mariners could also use a combination of Dylan Moore and utility man Sam Haggerty at second base and left, and Lewis is still at least two weeks away.

MLB Pipeline No. 4 overall prospect Jarred Kelenic is not an option due to the reps that the team wants him to accumulate in the Minors.