SEATTLE -- Until Mitch Haniger’s recent setback, it was fairly easy to pencil out a projected Mariners lineup heading into Spring Training. But Haniger’s sports hernia surgery changes the picture as right field, and perhaps both corner outfield spots, now are up in the air in Seattle’s rebuilding scenario.

In another sharp reminder of how quickly things can change, instead of the Mariners keeping an eye on Haniger’s comeback from an injury-plagued 2019, this spring will now feature an intriguing position battle in camp between rookies Jake Fraley, Braden Bishop and the recently acquired Jose Siri, as well as an increased opportunity for an early peek at prized prospects Julio Rodriguez and Jarred Kelenic.

The presumption has been that fellow rookie Kyle Lewis would open the season in left field following his shiny September debut, with Mallex Smith returning in center field as the lone “veteran” in the group at age 26.

Lewis hit six homers in 18 games last September while playing primarily in right field in Haniger’s absence. So the 2016 first-round Draft pick could slide back into right again and let Fraley, Bishop and the others battle it out in left.

But one way or another, one of the corner outfield spots is now up for grabs -- and the ones doing the grabbing are all rookies.

"The one certainty on our Major League club in the outfield is that Mallex will play,” general manager Jerry Dipoto said. “Beyond that, it's a wide-open field. We want to see Kyle Lewis take the ball and run with it and expect that'll happen. It probably creates more of an opportunity for Jake Fraley to make the Opening Day club and a regular role rather than moving around in more of a timeshare.”

Here’s a look at all the options:

The returning favorites
Fraley, 24, had a strong year at Double-A Arkansas and Triple-A Tacoma last year, combining for a .298/.365/.545 slash line with 19 homers, 80 RBIs and 22 stolen bases in 99 games. But he struggled in a short stint with Seattle, hitting .150 in 40 at-bats over 12 games before spraining his right thumb and missing the final three weeks.

Injuries limited Fraley to 96 games combined in the Rays’ Minor League system from 2017-18 and the Mariners felt he wore down physically over the course of the long haul last year, so they’re interested to see how he does now after bulking back up this winter.

Bishop, 26, is another rookie who will need to show he’s stronger again after the slender speedster missed three months in midseason with a lacerated spleen after taking a fastball to the ribs. The University of Washington product returned in September but hit just .125 (4-for-32) in 17 games with no extra-base hits.

The Mariners love Bishop’s mental makeup and how he remade his swing in recent years, and he’s regarded as the best defender in the group, capable of playing an excellent center field or either corner. The bat will need to play in order for Bishop to win a starting spot, but he certainly is in the mix for at least a backup job with his versatility and glove work.

The newest addition
Siri, claimed off waivers from the Reds on Monday, could be a wild card in the competition. The 24-year-old was regarded as one of Cincinnati’s elite prospects three years ago with a breakout year at Class A Dayton, but has struggled offensively since climbing the ladder.

The Mariners are intrigued by his five-tool potential as a defensive standout with power and speed and will see if they can improve his contact rates and swing decisions at the plate.

“He’s a tool shed,” Dipoto said. “We’ll see if we can help him out. We think we can. He has a [Minor League] option, and we’ll figure out where he fits for us and if we can help him, because he has multiple well-above-average tools. He has power potential; he can really run and play defense. There’s a lot of things he can bring to the table, and we’ll see if we can unlock them. That was an easy one, a low dollar investment on a really high ceiling.”

The future
Dipoto has told Kelenic he’ll almost certainly start the season in Double-A Arkansas, with Rodriguez ticketed for Class A Advanced Modesto.

No matter how good they look in camp, the Mariners don’t want to push their top two prospects before they’re ready. But that doesn’t mean their MLB futures are far away. Kelenic jumped two levels last year, and if the 20-year-old continues shining, he could be in Seattle by the end of this season.

Rodriguez, 19, is one level behind, but the 6-foot-4, 225-pounder already has the physical look of a Major Leaguer, and some scouts believe has the higher upside of the two. How this season plays out for the dynamic duo remains to be seen, but the opportunity will be there to rise quickly if they show they’re ready at each stop.

“We are opening the door for Jarred Kelenic to do the same thing he did last year, which is prove that he belongs at the next level,” Dipoto said. “Just go do what you do to progress. And you know, if Julio has a good year in Modesto, awesome. He's 19. A good year in Modesto for a 19-year-old is a phenomenal thing. See Jarred Kelenic.

“We don't anticipate any of these players having to play in the big leagues [this year]. Nor do we want to force it. So they usually let you know when it's their time and we want to be flexible enough with our roster that when they tell us it's time, we give them their opportunity.”