He made his competitive debut against Bath Rugby on the opening day of the campaign and backed that up with a solid performance against Leicester Tigers last weekend.
Hill said: "John is doing very well. From a defensive point of view he has slotted in very nicely. Week-by-week he is getting better. He is very mobile around the pitch and he makes his tackles. It's a very good signing for us so I'm pleased.
"It was a tough afternoon for John at Welford Road last Saturday but he performed well and he will grow with every game he plays."
Hill was also quick to praise fellow summer signing Josh Matavesi and thinks the 22-year-old has a bright future at the club.
He added: "Josh is a very exciting player. He has work to do in defence but his attacking threat is excellent and he gives us a new dimension.
"He is a very good signing for us. He is a young man who is very confident and has a lot of enthusiasm.
"He just enjoys his rugby and his infectious enthusiasm goes to everyone else. I think he's going to be a big talent - we've found a really good player there."