The contest was expected to open the FOX main card on July 26 from the SAP Center in San Jose. Robbie Lawler and Matt Brown meet that night in the main event to determine the No. 1 contender to welterweight champion Johny Hendricks.
Johnson (15-8) has won three straight since back-to-back losses to Reza Madadi and Myles July. In March, he defeated Melvin Guillard, while also holding wins over the likes of Joe Lauzon, Danny Castillo and Tony Ferguson.
Thomson (20-6) lost to Benson Henderson in January, costing him his spot as the No. 1 contender to the belt. He has alternated wins and losses in his last six fights, including a defeat to Gilbert Melendez in 2012.
UPDATE: Officials have announced Bobby Green as a replacement for Johnson, moving Green from a fight at UFC Fight Night 47 against Abel Trujillo. Full story at FightLine.com.