Hisashi Iwakuma. The Mariners shouldn't be any rush to deal Iwakuma, who's controlled for two more seasons at an affordable cost of $13.5 million. He's coming off a season in which he created better results than Felix Hernandez, and though he seems unlikely to repeat the same level of elite performance, he's still been a terrific surprise who the Mariners will lean on over the next two seasons to stabilize their rotation as young prospects Taijuan Walker and James Paxton join.
There's also consideration that the Mariners may be able to extend Iwakuma again after his deal runs up. Iwakuma quickly signed back on after his first one-year deal expired, and Seattle has always maintained a positive relationship with Japanese players.
It also seems unlikely that Iwakuma will net the kind of return the Mariners should be looking for, and given his smaller track record than somebody like David Price or Max Scherzer, it seems likely he'd be a less preferable, but less expensive target for teams looking to bolster the front of their rotation. If Iwakuma can possibly perform as well as those two but net a far lesser return, there's a problem moving him.
Brad Miller. The Mariners simply don't have any current depth at shortstop behind Miller, and he demonstrated the ability to adjust at the plate throughout his rookie season. He's unlikely to ever be a superstar, but could round into a 3-4 win player at the hardest position to field. He still has plenty of potential to grow at the plate, and his defensive mistakes are often mental - something that may improve with more and more experience. Miller is the kind of player the M's should be looking to acquire, not trade - and short of a blockbuster deal for a superstar with an external replacement lined up - Miller should stay put.
Nick Franklin/Dustin Ackley. This is a tough one, because the Mariners do have the luxury of a surplus at second base. Franklin and Dustin Ackley are both talented players who went through major adjustment periods. Franklin's has been much shorter, but his start with a bang and fade away trend is all too familiar - it's easy to forget how much better Dustin Ackley's rookie season was than Nick Franklin's. Still, one of these guys is a prime candidate to get shipped off for an upgrade in another position, and I'm torn on which one it should be. Ackley is the better overall defender at second, but Franklin likely has more trade value, since he hasn't burned nearly the same amount of club control and has struggled for far less time.
The return is what matters more than the player in this scenario. The Mariners absolutely should listen on all inquires, but don't force a deal just because there's a surplus. Both of these players still have big time potential, and selling too low on either would be a disservice to the team.
Yoervis Medina. Despite massive control problems, Medina finished the season with a 2.91 ERA. He only allowed a .257 BABIP, and outperformed peripherals of 3.85 xFIP and 3.76 SIERA. He was also exceptionally good (lucky?) at stranding runners (82.6%).
This probably isn't going to happen again. At least not if he's going to continue walking that many batters. When you allow a bunch of baserunners, your luck is eventually going to run out, and Medina's trade value may be higher now than it ever will be. Young, power throwing RHP averaging 94 mph on the gun - any team looking for relief help might look at the pure results and lick their lips.
Still, only Carlos Marmol and Al Alburquerque had worse control last year, and both of those guys struck out more batters with higher BABIP and lower LOB%. Regression is coming for Medina, and while he could still be a solid member of the bullpen in 2014, his ERA seems unlikely to be beneath 3 again. He's a sell-high candidate.
Must get rid of
Raul Ibanez. There's nobody on the team that the Mariners have to trade, but they really need to move on from Raul. I've already laid out the full argument for this, so I won't repeat myself. Thanks for what you've done, but go out on top like Costanza.