SCOTTSDALE, Ariz. -- Yasmany Tomas' quest to make the D-backs' Opening Day roster came to an end on Sunday when the outfielder was optioned to Triple-A Reno.Tomas, who had been a regular in the lineup when healthy over the past two seasons, faced an uphill battle this spring when the

SCOTTSDALE, Ariz. -- Yasmany Tomas ' quest to make the D-backs' Opening Day roster came to an end on Sunday when the outfielder was optioned to Triple-A Reno.

Tomas, who had been a regular in the lineup when healthy over the past two seasons, faced an uphill battle this spring when the D-backs signed free agent outfielder Jarrod Dyson and traded for outfielder Steven Souza Jr.

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The pair were added just as camp opened, and the D-backs told Tomas he was going to have to fight for a spot on the roster.

The 27-year-old performed well at the plate with a slash line of .293/.370/.439, but the D-backs are placing a high premium on defense this year and that has never been a strength for Tomas.

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"Those are the things that we talked about -- that he needs to go and work on his defense," D-backs manager Torey Lovullo said of his meeting with Tomas on Sunday morning. "It's adequate, but we want it to improve on a level where he's going to be an above average defender. That was spelled out to him. He had a great camp offensively, and defensively, we are still trying to piece together his game."

Tomas was signed to a six-year, $68.5 million deal out of Cuba in December of 2014. At that time, it was the richest free-agent deal in franchise history. Tomas is set to earn $9.5 million this year, and has a two-year player option which would pay him $15.5 million in 2019 and $17 million in 2020.

The club initially wanted Tomas to play third base, but early in his first spring with the D-backs, it was clear that was not going to work, so he was moved to the outfield.

In 2015, he hit .273 with nine homers and 48 RBIs in 406 at-bats, and then he hit .272 with 31 homers and 83 RBIs in 530 at-bats in 2016.

Last season, though, Tomas was limited to 47 games due to injuries, which resulted in a pair of surgeries, and he slumped to .241 with eight homers.

With David Peralta , A.J. Pollock and Souza set to start in the outfield, with Dyson being viewed as the primary backup to all three, Tomas' chances of making the roster were long.

Even with Souza set to start the year on the disabled list with a strained pectoral muscle, the D-backs appear to prefer having Chris Owings get reps in the outfield rather than Tomas.

Arizona acquired infielder Deven Marrero on Saturday, which freed up Owings to play more outfield if needed.