Mower starts and stays engaged

I have a Craftsman YTS 4000 lawn mower. My drive belt recently jumped track and from what I read it was going to be best to change it and the deck belt at the same time. I read in forums and researched to make sure I did the job correctly. Once I finished I cranked her up to find I had drive power again, however quickly realized my decked was engaged with the lever in the off position. The deck sounds rather rough while its running. This is where I hit the wall since I haven't found any similar problems online. Hoping an expert can really help me out. PS I have triple checked belt routes, sizes and quality before and after.

Hello, is it a manual arm that engages the blades or a button/switch?