Jones played for Moseley and London Welsh last season as he continued his fight back from a serious knee injury.
"Matthew is a quality player who caught my eye when I was national coach with Wales," said Ruddock.
"He has worked his way back from this injury and I have no doubt that he can perform to the same level that made me pick him for the full Wales team."
Jones will compete with Samoan international Loki Crichton and Joe Carlisle for the No 10 jersey at Sixways.
"It's a great opportunity and one I intend to take with both hands. I can't wait to play in the English top-flight and show what I am about," said Jones.