1. Justus Sheffield, LHP

Where he’ll start: Class AAA Tacoma

What to watch: Sheffield made his major-league debut in 2018 with the Yankees — appearing out of the bullpen three times — and then became the centerpiece of the James Paxton trade this winter. After a strong spring with the Mariners, the 22-year-old appears just about ready to step into the big-league rotation. Veteran starters Felix Hernandez, Mike Leake and Wade LeBlanc don’t fit in with the Mariners’ rebuilding plans, and if one of them is traded or moved to the bullpen, Sheffield should be first in line to join the M’s rotation. He will start the season in Tacoma to refine his command, but count on a call-up to Seattle by midseason.

ETA to the Mariners: Soon. Very soon.

Jarred Kelenic chases a ball March 9 in Phoenix. (Sue Ogrocki / The Associated Press)
Jarred Kelenic chases a ball March 9 in Phoenix. (Sue Ogrocki / The Associated Press)

2. Jarred Kelenic, OF

Where he’ll start: Class Low-A West Virginia

What to watch: The No. 6 overall pick out of Waukesha, Wis., Kelenic was the top high-school player selected in the 2018 draft. The Mariners, who held the 14th pick, had shown strong interest in him leading up the draft, and Kelenic was not surprised to later learn the New York Mets had traded him to Seattle in the Robinson Cano-Edwin Diaz blockbuster. Kelenic makes consistent contact with a compact, left-handed swing, and he’s athletic enough to project as a future center fielder in the big leagues. Kelenic played 56 games of rookie ball in 2018, posting a .286/.371/.468 slash line with six homers, 15 steals, 26 walks and 50 strikeouts in 174 at-bats. The Mariners won’t want to rush his development, but his makeup suggests he might be able to move through the system relatively quickly.

ETA to the Mariners: 2022.

Evan White takes a pickoff attempt Feb. 24 in Scottsdale, Ariz. (Dean Rutz / The Seattle Times)
Evan White takes a pickoff attempt Feb. 24 in Scottsdale, Ariz. (Dean Rutz / The Seattle Times)

3. Evan White, 1B

Where he’ll start: Class AA Arkansas

What to watch: It’s not a stretch to suggest White might be the best defensive first baseman in the minor leagues, if not all of baseball, and his glovework has already drawn comparisons to the likes of Todd Helton and John Olerud. The Mariners’ 2017 first-round pick, White is Baseball America’s No. 100 overall prospect going into 2019. He had a solid season at the plate in Class High-A Modesto in 2018, and he hopes a late-season swing adjustment will carry over positive results this season. At a lean 6 feet 3 and 205 pounds, White doesn’t project as a classic power hitter, but his hit tool is good enough to project him as the Mariners’ long-term answer at first.

ETA to the Mariners: 2020.

Julio Rodriguez strikes out swinging March 9 in Phoenix. (Sue Ogrocki / The Associated Press)
Julio Rodriguez strikes out swinging March 9 in Phoenix. (Sue Ogrocki / The Associated Press)

4. Julio Rodriguez, OF

Where he’ll start: Class Low-A West Virginia

What to watch: Rodriguez was the MVP of the Dominican Summer League as a 17-year-old right fielder last year, and he’ll make the jump to Low A to start this season. In West Virginia, he’ll join Kelenic in what the Mariners hope is a long-term partnership in the outfield. Rodriguez is 6-3 and 227 pounds with raw power; he has a strong lower half and a long, powerful swing. Baseball America writes that Rodriguez is a “smart hitter for his age with very good control of the zone and the ability to make adjustments at the plate. … It would not be a surprise to see Rodriguez at the top of the Mariners’ prospect list heading into 2020.”

ETA to the Mariners: 2022.

Outfielder Kyle Lewis exits the batting cage Feb. 18 in Peoria, Ariz. (Dean Rutz / The Seattle Times)
Outfielder Kyle Lewis exits the batting cage Feb. 18 in Peoria, Ariz. (Dean Rutz / The Seattle Times)

5. Kyle Lewis, OF

Where he’ll start: Class AA Arkansas

What to watch: His career stalled by a devastating knee injury in July 2016, Lewis says he is “fully healthy” now and was a full participant in spring training for the first time. This is a vital year for the development of the 2016 first-round pick, whom the Mariners still believe can be an everyday corner outfielder in Seattle in the not-too-distant future.

ETA to the Mariners: 2020.

Mariners pitcher Justin Dunn on Feb. 16 in Peoria, Ariz. (Dean Rutz / The Seattle Times)
Mariners pitcher Justin Dunn on Feb. 16 in Peoria, Ariz. (Dean Rutz / The Seattle Times)

6. Justin Dunn, RHP

Where he’ll start: Class AA Arkansas

What to watch: Dunn was another piece acquired from the Mets in the Cano-Diaz deal, and if all goes well this summer, Mariners’ fans could see him pitching at T-Mobile Park sometime in the second half of this season. A reliever at Boston College, Dunn was developed as a starter in three seasons in the Mets’ system, posting a 4.22 earned-run average with 105 strikeouts in 15 starts (90 innings) in Class AA last year. His arsenal includes a 93- to 95-mph fastball, a wipeout slider and an improved changeup. MLB.com lists him as the No. 89 overall prospect in baseball.

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ETA to the Mariners: Late 2019 or early 2020.

Logan Gilbert pitches for Stetson in 2018. (Photo courtesy of Stetson University / Romeo T Guzman / ASUN / Sideline Sports)
Logan Gilbert pitches for Stetson in 2018. (Photo courtesy of Stetson University / Romeo T Guzman / ASUN / Sideline Sports)

7. Logan Gilbert, RHP

Where he’ll start: Class Low-A West Virginia

What to watch: The Mariners’ 2018 first-round pick out of Stetson University, the 6-foot-6 Gilbert is scheduled to make his professional debut in West Virginia. He was shut down last summer after being diagnosed with a severe case of mononucleosis just days after the draft. White has touched 97 mph and has a four-pitch arsenal, and some scouts believe he could progress rapidly through the minors.

ETA to the Mariners: 2021.

Seattle second baseman Shed Long on Feb. 21 in Mesa, Ariz. (Dean Rutz / The Seattle Times)
Seattle second baseman Shed Long on Feb. 21 in Mesa, Ariz. (Dean Rutz / The Seattle Times)

8. Shed Long, IF

Where he’ll start: Class AAA Tacoma

What to watch: Long, acquired in a three-team trade with the Yankees and Reds, had a quick start in his first spring with the Mariners and will likely find his way to Seattle at some point this summer. Long has the on-base skills the Mariners’ covet — with an OBP of .353 in 1,635 minor-league at-bats — and the versatility to help a big-league club at second base, third base or in the outfield.

ETA to the Mariners: 2019.

Braden Bishop, center, takes his cuts in the batting cage March 17 in Tokyo. (Dean Rutz / The Seattle Times)
Braden Bishop, center, takes his cuts in the batting cage March 17 in Tokyo. (Dean Rutz / The Seattle Times)

9. Braden Bishop, OF

Where he’ll start: Seattle

What to watch: The former UW center fielder has been one of the best stories of spring as he claimed a surprising spot on the Mariners’ travel roster to Japan. He earned it with a torrid month in Arizona, during which he hit .379 with a 1.143 OPS, two doubles, a triple, three homers and 15 RBI in 15 spring games. Once Mallex Smith is healthy, Bishop will likely be optioned to Tacoma, but there’s little doubt Bishop will be back with the big club soon.

ETA to the Mariners: 2019.

10. Noelvi Marte, IF

Where he’ll start: Dominican Summer League

What to watch: The Mariners signed Marte for $1.55 million out of the Dominican Republic as a 16-year-old last summer. Listed at 6 feet and 187 pounds, he currently projects as a shortstop. MLB.com writes: “Marte is a big power bat, and big power bats play. … One scout dropped a young Miguel Cabrera comparison on him, while another evaluator believes Marte could eventually hit .270 and hit 25-30 home runs in the big leagues.”

ETA to the Mariners: 2023.

Jake Fraley and Shed Long talk hitting in the Mariner dugout Feb. 24 in Scottsdale, Ariz. (Dean Rutz / The Seattle Times)
Jake Fraley and Shed Long talk hitting in the Mariner dugout Feb. 24 in Scottsdale, Ariz. (Dean Rutz / The Seattle Times)

11. Jake Fraley, OF

Where he’ll start: Class AA Arkansas

What to watch: The second piece, after Mallex Smith, in the trade that sent Mike Zunino to Tampa Bay, Fraley opened the Mariners’ eyes this spring, posting a .960 OPS with two homers in 26 at-bats. Injuries limited him in three seasons in the Rays’ system, but a swing change appears to have rejuvenated his chances at reaching the majors.

ETA to the Mariners: 2020.

Mariners pitcher Erik Swanson throws Feb. 24 in Scottsdale, Ariz. (Dean Rutz / The Seattle Times)
Mariners pitcher Erik Swanson throws Feb. 24 in Scottsdale, Ariz. (Dean Rutz / The Seattle Times)

12. Erik Swanson, RHP

Where he’ll start: Class AAA Tacoma

What to watch: Another piece acquired in the Paxton deal with the Yankees, Swanson, 25, is another riser who could make his major-league debut in Seattle at some point this year. The 6-3 right-hander made 13 starts for the Yankees’ Class AAA team last year, finishing with a 3.86 ERA, walking just 14 and striking out 78 in 72 innings.

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ETA to the Mariners: Late 2019 or early 2020.

Catcher Cal Raleigh congratulates Florida State pitcher C.J. Van Eyk in 2018. (Gerry Broome / The Associated Press)
Catcher Cal Raleigh congratulates Florida State pitcher C.J. Van Eyk in 2018. (Gerry Broome / The Associated Press)

13. Cal Raleigh, C

Where he’ll start: Class High-A Modesto

What to watch: A switch-hitting catcher, and the son of a former college coach, Raleigh was one of the top catchers in college baseball at Florida State. The Mariners drafted him in the third round last year, and Raleigh began his pro career in Everett, where he had a .288/.367/.534 slash line with eight home runs, 10 doubles and one triple in 38 games.

ETA to the Mariners: 2022.

Sam Carlson, the Burnsville, Minn. right-handed high school pitcher drafted by the Seattle Mariners in the second round of the baseball draft, and Mariners manager Scott Servais, right, watch batting practice in Minnesota in 2017. (Jim Mone / The Associated Press)
Sam Carlson, the Burnsville, Minn. right-handed high school pitcher drafted by the Seattle Mariners in the second round of the baseball draft, and Mariners manager Scott Servais, right, watch batting practice in Minnesota in 2017. (Jim Mone / The Associated Press)

14. Sam Carlson, RHP

Where he’ll start: Class Low-A Everett

What to watch: The Mariners’ second-round pick in 2017, Carlson missed all of 2018 as he recovered from Tommy John surgery. He is not expected to start throwing again until July, and he may not throw in a game until 2020.

ETA to the Mariners: 2022.

Dom Thompson-Williams scores from third Feb. 23 in Peoria, Ariz. (Dean Rutz / The Seattle Times)
Dom Thompson-Williams scores from third Feb. 23 in Peoria, Ariz. (Dean Rutz / The Seattle Times)

15. Dom Thompson-Williams, OF

Where he’ll start: Class AA Arkansas

What to watch: The final piece in the Paxton trade, Thompson-Williams is coming off his best pro season, in which he hit 22 homers and stole 20 bases between two Class A stops in the Yankees’ system.

ETA to the Mariners: 2020

Mariners Preview 2019

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