The fullback has just suffered a back injury this week.
"He is doing very well," said Walcott to arsenal.com. "I don't think he thought he would be playing quite this much but Carl's got in there and he always wants to learn, which is great to see.
"He's eager, he wants to perform and he is getting better every game now. I think the game against West Brom a couple of weeks ago was his best game for us.
"He's got bags of confidence at the moment, all the lads are encouraging him and it's showing in his performances."