SEATTLE -- At long last, Opening Day is here. The Mariners will open the regular season on Thursday against the Giants at T-Mobile Park, and they've finalized who will be part of their 26-man roster.

With reigning American League Rookie of the Year Kyle Lewis on the 10-day injured list for at least the next few weeks due to a bone bruise in his right knee, Seattle had to make some last-minute adjustments. That essentially opened the door for Jake Fraley to make the team and play in left, with Taylor Trammell slated to fill in for Lewis in center field.

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Also, Drew Steckenrider won the eighth and final bullpen spot over Domingo Tapia, who was optioned to the alternate training site on Wednesday. In addition to Lewis, Shed Long Jr. (right shin) was placed on the 10-day IL and Ken Giles (Tommy John surgery) landed on the 60-day IL.

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Beyond the challenges of ramping up from a 60-game sprint back to a six-month marathon, MLB rosters will return from 28 to 26 players, leaving the Mariners with fewer spots to go around.

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With that in mind, here is a breakdown of who will be in the Mariners' dugout and bullpen on Thursday:

Catcher (2): Tom Murphy, Luis Torrens
Mariners manager Scott Servais said last month that playing time will be a 55-45 split to begin the season, with Murphy in the pole position. The 29-year-old showed major defensive strides in 2019 -- when he was also the Mariners' best bat -- before sustaining a broken bone in his left foot that cost him all of ’20. Murphy got off to a slower start in Spring Training, hitting .190/.277/.357. Torrens had an impressive showing offensively after coming over in a Trade Deadline deal with the Padres, though his catching could use some work. Because Ty France was catching as recently as last year at San Diego's alternate training site, he will be the emergency catcher and also give Servais insurance to include both Murphy and Torrens in the lineup on the same days if matchups dictate.

First base (1): Evan White
After going hitless during a two-week stretch in camp, White's bat came alive over the final week, and he finished the Cactus slate with a team-high 16 RBIs. The bat is the biggest area of both potential and concern for the 24-year-old, who wowed with his defense by becoming the first rookie first baseman to win a Gold Glove Award in MLB history. White's revamped setup in the box, with his hands lower, has helped him make consistent contact. And since there will be a Minor League season this year, the Mariners will have that to fall back on if White needs more offensive development. José Marmolejos and France are first-base reinforcements.

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Second base (1): Dylan Moore
This was the most contested position battle entering camp, but the competition essentially ended before it even started due to Long's surgically repaired right shin not progressing as quickly as he and the club had hoped. Moore warranted more playing time beyond the utility role after posting a 139 OPS+ last season. The Mariners acknowledge that he might be better suited for the utility role long term, but for now, they’d like to get him regular at-bats. France will also see action here.

Third base (1): Kyle Seager
The Mariners have been writing Seager’s name into the lineup for 10 straight seasons, and they will do so again in 2021. Seager is the highest-paid Mariners player at $18 million for '21, with a $15 million team option for '22 that becomes a player option if he’s traded. That contract, and the fact Seattle didn’t have a top third-base prospect in waiting, has resulted in Seager being the last remaining veteran still on board -- but the Mariners do have a viable option now after acquiring France from the Padres at the Trade Deadline. Seager also had a stellar spring, hitting .350/.469/.500.

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Shortstop (1): J.P. Crawford
The 26-year-old has quickly become one of the staples in the Mariners’ rebuild, and his big defensive strides since coming over in a 2018 trade paid off in ’20 with his first Gold Glove Award. Crawford also showed improvement with his bat, enough to assume the everyday leadoff spot last year, though the return of Mitch Haniger will drop Crawford lower in the lineup. The Mariners think there is a higher ceiling at the plate than the .255/.336/.338 slash line Crawford posted in 2020. He is coming off a spring in which he went 5-for-39 (.128/.346/.128).

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Outfield (3): Mitch Haniger, Taylor Trammell, Jake Fraley
The outfield was already a little more in flux with Lewis in the mix, and it becomes more uncertain with his injury. Haniger is the Mariners’ best position player, has looked every bit the part this spring and has emerged as the everyday leadoff man. But Servais has said that the club will likely ease him in by playing just four or five days per week early as he underwent multiple surgeries last year.

Trammell was arguably the most impressive player throughout Spring Training -- certainly the one that made the biggest ascent. He hit .311/.392/.644 with three homers, had exit-velocity readings approaching 115 mph and made eye-opening plays on the basepaths and in the field. It'll be interesting to see how he adjusts, given that this will be the first big league action for the 23-year-old.

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Fraley was the frontrunner entering camp for the left-field job, and though an 0-for-15 start put his status in doubt, he rebounded to finish with a .250/.400/.386 slash line.

No. 1 prospect Jarred Kelenic should earn a big portion of the playing time in left over the course of the 162-game regular season, but the key question is when. The Mariners have informed the confident left fielder that "the finish line is right there" on his Minor League development, but they want him to get more at-bats in the mid-to-high-level affiliates before calling him up.

Designated hitter (1): Ty France
No hitter in Mariners camp -- heck, maybe even all of the Majors -- was hotter than France, whose 1.135 OPS was the seventh highest in the big leagues. He's shown more and more why the Mariners have called him an "everyday" player and intend to inject his bat in the lineup. Though he'll spell some infielders throughout the year, his primary position in 2021 will be at DH.

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Bench (2): Sam Haggerty, José Marmolejos
Because Seattle will carry 14 pitchers, there will be only two bench jobs open after accounting for the backup catcher. That essentially cuts the fourth outfielder role, which is why versatility here will be huge.

Haggerty can play all over the field, and he runs the bases well. He also showed some offensive potential with a .260/.315/.400 slash line in 13 games in ’20, and he's got pretty good backing from Servais, too.

Marmolejos can play left field and first base, and he's a left-handed bat, which gave him an edge. He's also out of Minor League options, so there was more incentive to put him on the 26-man roster.

Starting pitchers (6): Marco Gonzales, James Paxton, Justus Sheffield, Chris Flexen, Yusei Kikuchi, Justin Dunn

The Mariners will again turn to a six-man rotation after seeing its benefits in 2020, a trend that will likely spread across baseball as MLB returns to the more demanding 162-game schedule. Seattle will be able to allocate a big chunk of those innings to the veteran Paxton and pair him at the top of the rotation with No. 1 starter Gonzales. Kikuchi benefits from the six-man because it allows for a fifth day of rest between starts, mirroring the schedule he had in Japan.

Flexen is the newcomer, returning to the Majors after a solid season in Korea. Sheffield is coming off a stellar rookie season, and he's taking a more location-driven approach that mirrors Gonzales into 2021. Dunn won the final rotation spot in a battle with Nick Margevicius, who will be the team's long man out of the bullpen for the early leg of the season, when pitch counts across the staff will be monitored closely.

Relievers (8): Rafael Montero, Kendall Graveman, Keynan Middleton, Anthony Misiewicz, Casey Sadler, Will Vest, Drew Steckenrider, Nick Margevicius
Montero will get the first looks at the highest-leverage innings after racking up eight saves in as many tries as the Rangers' closer last season. Graveman is next on that list after a successful transition to the bullpen -- which featured some of the highest velocity readings of his career -- following his return from a benign tumor last season. Middleton also brings gas and closing experience. Beyond those three, Misiewicz was one of the Mariners' better relievers last year, Sadler pitched his way onto the team with a strong spring (he's also out of options), the Rule 5 Draft selection Vest had enough intrigue with his pure stuff to extend his audition and Steckenrider won the eighth spot against Domingo Tapia, who is just recently recovered from an oblique injury.