Seattle, WA (SportsNetwork.com) - The Seattle Mariners announced on Wednesday that pitcher Hisashi Iwakuma will be sidelined from 4-to-6 weeks with a finger injury, leaving him unavailable for Opening Day.

The 32-year-old right-hander injured the middle finger on his throwing hand in preparation for spring training and was diagnosed with a strained tendon by hand specialist Dr. Don Sheridan. His finger has been placed in a splint and he will not throw for at least a month until being re-evaluated.

"Luckily, this does not appear to be a serious injury," said Mariners general manager Jack Zduriencik. "It is a setback for (Iwakuma), but we are confident that he will quickly overcome the missed time and be able to rejoin our rotation early in the regular season."

Iwakuma had a stellar season in his second big league campaign last year, compiling a 14-6 record with a 2.66 ERA over 33 starts for the Mariners.

A native of Tokyo, Iwakuma ranked third in the American League in ERA and finished third in the 2013 AL Cy Young voting behind Detroit's Max Scherzer and fellow Japanese pitcher Yu Darvish of Texas.

Iwakuma, who became a perfect compliment to Seattle ace Felix Hernandez, has a 23-11 career record with two saves and a 2.84 ERA over 63 major league games.