The on again, off again Josh Thomson-Gilbert Melendez bout is officially off Strikeforce’s Aug. 15 card. A text message sent by organization spokesman Mike Afromowitz stated that doctors would not clear Thomson for the fight.

Melendez (15-2) will now square off against Mitsuhiro Ishida in a five-round rematch for the interim Strikeforce lightweight title. Ishida (18-5-1) defeated Melendez in a 2007 New Year’s Eve contest in Japan, giving him his first defeat as a professional. News of the opponent change was first reported on graciefighter.com, a Web site ran by Melendez trainer, Cesar Gracie.

Gracie also confirmed the news, stating that Melendez was thoroughly disappointed his rematch with Thomson was being delayed yet again.

“Gilbert did not come into the first fight in shape, he is in great shape right now and is upset he will not get a chance to fight Josh,” said Gracie.

Gracie also told Sherdog.com that Melendez is looking forward to evening the score with Ishida. He did warn that his charge will have to be wary of Ishida’s improved submission skills if he is going to get past the tough Japanese wrestler.

Thomson’s trainer, Bob Cook, confirmed to Sherdog.com that his fighter was forced out due to a new break -- a hairline fracture just above a metal plate that was inserted in his leg after the original injury. Cook stated that Thomson kicked him in training about three weeks ago, and tried to work through the injury in hopes of competing. Those hopes were dashed when x-rays showed the fracture and he was advised not to fight.

This article was updated at 6:35 p.m. ET to add information obtained from Cook.