Acquired via free agency on December 17th, 2015 and on November 27, 2017
We pulled a fast one you. Yes, Iwakuma was on the Mariners before Jerry Dipoto took over late in the 2015 season. But Dipoto still re-signed Iwakuma twice, so he is most certainly eligible as a Dipoto transaction.
Iwakuma may be the most underrated starting pitcher in franchise history and should be a candidate to make the starting rotation of the All-Mariners team, not just the list we are currently compiling.
Unfortunately, Iwakuma’s best years came under the Jack Zduriencik regime but Iwakuma was still productive with Dipoto at the helm, making 39 starts and compiling a 2.7 bWAR as a member of Dipoto’s Mariners. Unfortunately, a shoulder injury cut short his final season in the big leagues and put a damper on an otherwise incredible career in Seattle.
But Iwakuma was one of the best pitchers in the AL for a 4-year stretch, including his final healthy season in which he threw 199 innings for the 2016 Mariners.
This is an interesting inclusion to our list. Dipoto didn’t discover Iwakuma, nor was he instrumental in getting Iwakuma to come to Seattle in the first place. But he did re-sign Iwakuma twice, and recognizing the value of a pre-established player is a skill good general managers need to possess.