The organization announced late Friday evening that Iwakuma agreed on a two-year extension through the 2014 season. The extension also features a club option for 2015. Financial details were not released.
“Hisashi did a very nice job for us at the end of last season as a starting pitcher and we are happy that we have come to a mutual agreement,” general manager Jack Zduriencik said in a press release. “We look forward to his veteran presence and to his contributions for the next few seasons.”
Had the two sides not reached an agreement, the 31-year-old Iwakuma would have become a free agent.
Iwakuma posted a 9-5 record with two saves and a 3.16 earned-run average overall in 30 appearances as both a starter and a reliever. He moved into the starting rotation late in the season, and went 8-4 with a 2.65 ERA in 16 starts. That set a club record for lowest ERA by a rookie starter, previously held by Felix Hernandez, who had a 2.67 ERA in 2005.
“Kuma really helped solidify our rotation in the second half of the season,” manager Eric Wedge said. “He is a competitor on the mound and did a great job for us. He got stronger with each start during the season.”
Iwakuma was a non-factor early in the season as he struggled to adjust to pitching at the major league level. But midway through the season, he became more effective and worked his way into the rotation.
Prior to joining the Mariners last season, Iwakuma compiled a 107-69 record in 226 career games with Kintetsu (2001-04) and Rakuten (2005-2011) in the Japan League. In 2008, he was named the Pacific League MVP and winner of the Eiji Sawamura Award – Japan’s equivalent of the Cy Young Award – after going 21-4 with a 1.87 ERA in 28 starts.
Ryan Divish: 253-597-8483 ryan.divish@ thenewstribune.com blog.thenewstribune.com/mariners @RyanDivish

