The 27-year-old has been a free agent since leaving MLS outfit Toronto.
“After training on Tuesday I said I didn’t support Ricketts’ signing due to our present financial situation,” Diosgyor head coach Barnabas Tornyi told the club’s official website.
“But our situation has now changed. Club officials explained the situation.
“I spoke to him face-to-face and he spoke about his experiences in football and he admitted he wasn’t in as good condition as he should be.
“I offered him the chance to attend extra training sessions within one month and he accepted this offer.”