Evans was a mainstay of the Leeds reserves in 2000-01 after making his debut against 1860 Munich in the Champions League qualifier. After only making two substitute appearances in 2000-01, and with little immediate prospect of advancement, he left on a free transfer to Huddersfield just before the start of the 2001-02 season.
"Steve and my agent got together and my agent asked him if I could come training," the 22-year-old told the club's official website.
"I have been here for two weeks and I have enjoyed it and have done okay, and the gaffer asked if I wanted to sign for a month which I did because I want to get back playing again."
Evans will get a chance to impress McMahon further during Wednesday's reserve game against Oldham Athletic.