The fight fallout is due to an undisclosed injury. MMAFighting.com confirmed an initial report Sunday by FloCombat.com.
Thomson (22-8), is a former Strikeforce lightweight champion. Since jumping to Bellator from the UFC last year and is 2-0 in the company with finishes in both victories.
Chandler, for his part, is a former Bellator lightweight champion who has put a three-fight losing streak in his rear-view mirror after winning his last two fights.
No word yet on a new opponent for Chandler for the May 14 card in San Jose, Calif.