Hartley said: “Kevin is a good signing for us and I am delighted to get him. He is a player I have watched over the last two years. We have also watched him around 15 times this season to see how he is doing.
“I think Kevin has good potential also at 22. We like what we see of him.
“We think he is at the right age that we are trying to bring in. The age of the squad is getting younger with the signings we have made.
“We are trying to progress the club and make the group better. We have had a good season making the top six but we have to improve on that next year.”