The Mariners aren’t expected to announce their Opening Day roster until as late as Wednesday, but some of the final decisions have already been announced by manager Scott Servais.

Much of the delay on the final roster is related to the health of center fielder Kyle Lewis, who has a deep bone bruise in his right knee that has put his status for Thursday’s regular-season opener in doubt. Servais even indicated that the club could explore the waiver wire to find an outfield reinforcement, though Seattle does have in-house options that could hold it over if the reigning American League Rookie of the Year can return quickly.

So, with no official word on the 26-man unit yet, we’ll play a game of what we know and what we don’t:

Emotional Trammell will be in OD lineup

No player made a more significant ascent this spring than Trammell, who entered camp as somewhat of an unknown after coming over in a Trade Deadline deal last Aug. 31 and playing his way into a starting job. The Mariners’ No. 6 prospect (MLB Pipeline’s No. 100 overall) will play the bulk of the innings in center field if Lewis is sidelined.

• One player on each team who wowed at camp

The 23-year-old Trammell is a little further along than the rest of Seattle’s top prospects, with five years of Minor League experience under his belt. So, when Servais informed Trammell that he made the team, emotions were high.

“He had his mask on and we were socially distanced, so I said, ‘You can take the mask off,’” Servais said over the weekend. “He had this big smile on his face. He actually teared up. It’s a lot for these young kids. They’ve been thinking about it their whole lives and what they go through and what their families go through to get to that point.”

Trammell hit .311/.392/.644 in 45 Cactus League at-bats, including an RBI double in a 5-5 tie with the Reds in Monday's Cactus League finale that nearly cleared the fence in the first inning. By the eye test and stat sheet, he’s earned the opportunity.

Margevicius headed to bullpen

Nick Margevicius lost the battle with Justin Dunn for the sixth and final rotation spot, but he will be included on the big league roster. The left-hander will be in Seattle’s bullpen as a long man for at least the first leg of the season.

Margevicius threw 3 2/3 innings in his final Cactus outing on Thursday, and the Mariners will want to keep him stretched out in case he’s needed in a pinch for the rotation. But with the workloads of all of Seattle’s pitchers being carefully monitored early in the season, even for veterans Marco Gonzales and James Paxton, there’s value in having an arm with multi-inning ability like Margevicius’ in the bullpen. That’s why he was included instead of former starter Erik Swanson, who never threw more than one inning in Cactus League play.

“It’s another left-hander in your bullpen, and I like the fact Marge is stretched out,” Servais said. “He can give you multiple innings out of the bullpen, and I think you need one of those guys down there. With a six-man rotation, you have one less guy in the bullpen to play with, so if a starter gives you a short outing, Marge can come in that ballgame and bridge the gap, or he can finish off games by giving you extended innings.”

Rule 5 pick Vest will break camp

Will Vest’s up-and-down spring ended with a stretch of five straight scoreless outings, which extended his long-term audition into the regular season. As a Rule 5 Draft pick from the Tigers last December, if Vest doesn’t remain on the 26-man roster throughout the season, he would be eligible to return to Detroit.

This will be Vest’s first big league opportunity after three seasons in the Minors, over which he’s compiled a 3.88 ERA and a 25.6 percent strikeout rate over 132 1/3 innings. He has a three-pitch mix headlined by an impressive changeup that he displayed regularly during Spring Training.

What about the final bullpen spot?

With Margevicius and Vest already confirmed, Rafael Montero, Kendall Graveman, Keynan Middleton and Anthony Misiewicz the other favorites and Casey Sadler out of Minor League options, the final spot in the eight-man ‘pen comes down to right-handers Domingo Tapia and Drew Steckenrider.

This decision is also related to health, with Tapia on the cusp of returning from an oblique injury that he sustained on March 5 against the Dodgers. If Tapia is healthy -- which he appears to be after hitting 99 mph in a recent live BP session -- he would be the favorite.

Anyone else?

If Lewis can’t go and the Mariners don’t turn to the waiver wire for an outfielder, expect Jake Fraley to break camp as the Opening Day left fielder. Fraley started spring hitless in his first 15 at-bats, but he rebounded to finish with a .250/.400/.386 slash line in 20 games.

Braden Bishop is the most superior defensive outfielder on the 40-man roster, which could keep him in consideration for some early-season reps, pending Lewis' status. But his bat lagged to a .150/.320/.200 slash line in 20 spring at-bats, and he was optioned to the alternate training site on Friday.