PORT CHARLOTTE, Fla. -- The Rays could be without high-leverage reliever Pete Fairbanks for a significant chunk of the season’s first half due to the lat muscle injury that forced him to leave his outing Sunday after throwing only five pitches.

Fairbanks had an MRI exam on Monday’s off-day, and the initial recommendation was that the right-hander be shut down from throwing for six weeks. The club is still seeking further information and sent Fairbanks to receive a second opinion on Tuesday, which could reveal more about his injury and alter his recovery timeline. Regardless, it seems likely Fairbanks won’t be returning to the mound any time soon.

“It's not ideal. He battled some injuries last year. This one, we're fairly confident, is strictly the lat,” manager Kevin Cash said Tuesday. “We'll let some specialists look at it and see, but he's going to be shut down, no-throw, for a period of time.”

If Fairbanks is limited to rest and rehab for the next six weeks, it would take him about that long to return once he’s cleared to resume throwing. In that scenario, he would pick up a ball in early May and return to action around mid-June. But the Rays hope to gain more clarity after he's further evaluated.

Fairbanks sustained the injury during Sunday’s 4-1 win over the Braves, when he recorded one out before rotating his shoulder and walking off the mound without throwing a warmup pitch.

Losing Fairbanks for an extended period would be a significant blow to Tampa Bay’s bullpen, which is already set to begin the season without right-hander Nick Anderson as he recovers from elbow surgery. Fairbanks, 28, was an effective late-inning arm when healthy last season, as he posted a 3.59 ERA with 56 strikeouts in 42 2/3 innings over 47 outings, but he served two stints on the injured list due to shoulder issues.

“I think we all know, when Pete's right, he's pretty special down there in what he's able to do. He's shown the ability to pitch out of jams, come in [in] sticky situations, because he just creates so much swing-and-miss,” Cash said. “A lot of guys can [do that] down there, but I would say when he's right, he's probably at the top of the list of getting strikeouts.”

The Rays still have a ton of bullpen depth, however, and they shouldn’t have any trouble filling out an expanded bullpen at the start of the season. All-Star righty Andrew Kittredge will lead the group as Cash’s top high-leverage option, and he’s joined by a group that includes new lefty Brooks Raley; righties J.P. Feyereisen, JT Chargois, Matt Wisler, Ryan Thompson, Jason Adam and Chris Mazza; and returning lefties Jeffrey Springs, Colin Poche and Jalen Beeks.

One benefit of what the Rays went through last season, when they used 38 pitchers and had 14 of them record at least one save, is that pretty much everyone has experience in high-leverage situations.

“It’s going to be an opportunity for somebody else,” Cash said.

KK on the mend
Center fielder Kevin Kiermaier, limited by a tight left groin the past few days, said he’s making “great progress” and hopes to return to game action soon. Kiermaier, whose spring got off to a delayed start due to a stiff neck, said he has been fully cleared for all on-field activities -- everything except playing in real games.

Kiermaier is hoping to return to the field Thursday or Friday, which would give him a week to prepare for Opening Day. Despite the time he’s missed in an already-abbreviated camp, the veteran believes he’ll have done enough work -- like tracking pitches during bullpen sessions and getting at-bats on backfields -- to be ready for first pitch on April 8.

“I'm confident I'll be ready,” Kiermaier said. “This is not how you draw it up with a couple of things in a shortened spring, but if anyone's going to get through it, it's me. I'm confident and ready to roll.”

Game notes
• Right-hander Drew Rasmussen gave up one run on two hits while striking out two over three innings in the Rays’ 4-2 win over the Twins on Tuesday at Charlotte Sports Park. Rasmussen unveiled a new wrinkle to his arsenal, adding essentially a second slider -- a bigger, sweeping breaking ball designed to make hitters swing and miss -- while tightening up his slider into something of a cutter/slider hybrid.

“The ability to just change shape and velocity on it, I think, is going to give me an extra option, which will be nice,” Rasmussen said. “The ability to throw both of those in the strike zone is going to be key, and I think we did a really good job of that today.”

• Lefty Brooks Raley and righty J.P. Feyereisen, two of the Rays’ high-leverage relievers, recorded more than three outs in Tuesday’s game. Raley worked 1 2/3 innings, and Feyereisen picked up four outs. The Rays expect half their relievers to be capable of working multiple innings at the start of the season. Relievers Matt Wisler, JT Chargois and Jason Adam each pitched a scoreless inning without allowing a hit. Yandy Díaz went 2-for-3 with two RBI singles, and Manuel Margot went 2-for-3 with a homer.

Up next
The Rays will head north to face the Orioles on Wednesday afternoon at Ed Smith Stadium in Sarasota, Fla. Left-hander Josh Fleming, a strong candidate to secure a multi-inning/bulk-inning spot on the Opening Day pitching staff, is set to start for Tampa Bay after working a quick inning in his Spring Training debut. First pitch is set for 1:05 p.m. ET.