The 27-year-old, who had been deemed surplus to requirements at Aston Villa, has linked up with Hughes for the second time after playing under the Welshman at Manchester City.
"I had a great relationship with Mark at Manchester City and I was desperate to work with him and his staff again," Ireland told BBC Sport.
"Mark knows how I play and how to get the best out of me. I do feel as though I've something to prove and I'm coming here to get myself back playing."
Ireland had been forced to train with Villa's development squad in the early part of the season.