Iwakuma was examined by hand specialist Dr. Don Sheridan in Arizona. Dr. Sheridan has diagnosed a strained tendon in his middle finger.
Iwakuma has had the finger placed in a splint, and will not throw for four to six weeks. He will be re-examined after three weeks. At this time, it is not expected that the finger will require surgery to repair.
"Luckily, this does not appear to be a serious injury," said 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."
Mariners pitchers and catchers are officially reporting to camp today, and will have their first workout tomorrow (February 13).