ST. PETERSBURG — What started as discussions with the Mariners over a minor trade turned into a big deal for the Rays, a six-player swap that could fill their biggest holes with the acquisition of shortstop Brad Miller and DH Logan Morrison.In dealing from their depth of starting pitchers, the Rays traded Nathan Karns, plus fringe lefty reliever C.J. Riefenhauser and outfield prospect Boog Powell to Seattle on Thursday for Miller, Morrison and reliever Danny Farquhar.Though Rays baseball operations president Matt Silverman said it was too early to assign specific roles, it seemed clear what they were thinking.Miller, a 26-year-old lefty swinger from Orlando, at the least will be the leading candidate to replace free agent Asdrubal Cabrera as the everyday shortstop or be a platoon starter. Though the Mariners tried to convert Miller into a Ben Zobrist-type super utility man, Silverman said the Rays see him as "someone who can play shortstop at the major-league level," with the versatility a secondary bonus. Miller hit .258 with 11 homers, 46 RBIs and a .730 on-base plus slugging percentage last season."We've liked him for a while. We've been impressed by his work at shortstop, and it's always a plus to have a left-handed-hitting middle infielder," Silverman said. "We'll take him and the many other guys we have and head into spring training feeling good about our situation in the middle infield." Those others include Tim Beckham and Nick Franklin, another Orlando-area product who was acquired from Seattle in July 2014.Though Morrison spent most of last season at first base, the Rays are likely to slot him at DH with the idea he is a more powerful upgrade over free agent John Jaso, at least unless they deal first baseman James Loney.The lefty-swinging Morrison, 28, hit 17 homers and knocked in 54 runs last season, though with a .225 average and a .685 on-base plus slugging percentage. A noted free spirit, Morrison, who will make around $4 million via arbitration in his last year before free agency, can also play the corner outfield, but Silverman said the Rays got him for what he can do at the plate. He hit a career-high 23 homers in 2011 with the Marlins."He certainly has the type of bat that fits in the DH role, and we're excited about that bat," Silverman said. "He's a professional hitter. He's got some pop from the left side. You add him to our lineup and we're immediately more formidable, especially against right-handed pitching."Farquhar, 28, is coming off a rough season in which he went 1-8 with a 5.12 ERA in 43 games during five stints in Seattle. The right-hander was better in his previous two seasons, logging 16 saves with an 0-3, 4.20 ERA mark in 2013 and an impressive 2.66 ERA with a 3-1 record and one save over 66 games in 2014. Farquhar (FAHR-kwahr) has an option remaining, so he can be sent to the minors.Karns, acquired from Washington in spring 2014 for catcher Jose Lobaton and two prospects, was the biggest piece the Rays gave up. Silverman said they had "a logjam" of starters with Matt Moore and Drew Smyly returning from injury, and Erasmo Ramirez emerging.Taking advantage of an unexpected opportunity to be in the rotation due to injuries, Karns, 27, had an impressive rookie season, going 7-5 with a 3.67 ERA in 27 games (26 starts). However, he didn't pitch after Sept. 8 due to tightness in his right forearm.Karns said he was "definitely surprised" to be dealt and that it "hadn't really hit me yet,'' but he was grateful for the opportunity he got with the Rays and excited to go to Seattle.Riefenhauser, 25, was 1-0 with a 5.52 ERA in 17 relief appearances during four stints with the Rays this year. Mariners GM Jerry DiPoto said Powell, 22, was "a pivotal piece" of the deal with the potential to help them in 2016. Powell, 22, split last season between Double-A Montgomery and Triple-A Durham, hitting .295 with an impressive .385 on-base percentage. He was acquired from Oakland in January in the Zobrist deal.