The 31-year old midfielder is on the verge of departing Fratton Park for the Whites with manager Neil Warnock looking forward to his impending arrival.
"I've always liked him since he was at Plymouth and I've followed him since then," he told the club's official website.
"He has good energy and the way we are at the moment you can't get enough good players in that area. I think he'll fit in well, he'll fight for his place and give us the competition. He'll be another good signing I think.
"He's got a knack for goals. I think he has got that in his locker.
"I'm looking for goals from midfield to help us with the loss of (Robert) Snodgrass. We need to compensate that even though we're looking to sign strikers. That will go a long way to help us with goals from other areas as well."