As you might recall, last winter the A's won the negotiating rights for Iwakuma with a $19.1 million bid. But when an agreement with Iwakuma couldn't be reached, he returned to pitch another year for the Rakuten Golden Eagles.
If you believe this quote (via MLB Trade Rumors), Iwakuma's preference is Seattle: "We've received terms from a number of clubs, but considering where I'm needed and an environment my family can live in, at present we're closest to a contract with the Mariners."
Now a free agent, Iwakuma made only 17 starts last season but posted a 2.42 ERA. He typically throws his fastball in the high 80s, but complements that pitch with a variety of killer off-speed offerings.