It appears the Mariners will begin the regular season without starter Hisashi Iwakuma, as the right-hander on Wednesday was diagnosed with a strained tendon in his right middle finger.
Iwakuma, who suffered the injury while working out in Southern California in preparation for Spring Training, will not throw for four to six weeks. The finger has been place in a splint for the time being and Iwakuma will be reevaluated in three weeks.
The injury is not expected to require surgery at this time, but will still delay his preseason throwing program significantly.
"Luckily, this does not appear to be a serious injury," said general manager Jack Zduriencik. "It is a setback for Kuma, 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 excelled last year in his first full season as a Major League starter, going 14-6 with a 2.66 ERA over 33 starts. He made his first All-Star appearance and finished third in the voting for the American League Cy Young Award.
Paul Casella is a reporter for MLB.com. Follow him on Twitter @paul_casella.