The 22-year-old left back was supposed to have been moving to the Galpharm last month but saw his move put on hold after he suffered a hairline fracture of the shin.
He has signed on for three years. Ritchie was delighted with the signing and told htafc.co.uk:
"He's a young lad with loads of talent and I'm chuffed to have finally sorted it all out.
"He had a stringent medical over the past couple of days and came through fine, although it will be a few weeks before he is able to play in the first team. Both the Doc and Lee Martin (physio) were very pleased with his progress and the injury appears to be progressing quicker than normal.
"The deal we have offered his is revised from the first one we offered and is based initially on Robbie playing a certain number of games with nothing up front. We will get him playing as soon as we can and it will give us extra cover on the left hand side which we felt we needed." 
Robbie Completes Hudds Move