The midfielder was outstanding for victory over Newcastle United on Monday night.
Arteta said, “We have been missing Tommy and he has this presence, this aura, that makes him a special player for us.
“Hopefully we can keep him fit because we can all see the difference he makes on the side and I think he was growing and getting better and better as the game was growing and evolving.
“Yes, he can [have more attacking freedom here than at Atletico Madrid], technically he is more than capable of doing that and he's great in both transitional moments as well.
“It will take him some time to understand a different way of thinking or doing [things] than what he was doing with the previous team he was involved in. He has all the characteristics that we need to make us better, that's for sure.
“His dynamism, his physicality, his creativity and the presence that nature has given him. You have that person on the pitch and you are able to dominate a game when it is needed and Thomas has this quality."