Wenger is counting on Walcott to prove Fabio Capello was wrong to dump him for South Africa.
After their win over Celtic, he told arsenal.com: "He is determined, highly determined. He works very hard. The season will start in two weeks, I cannot say now who will have a great season or not, I just say that we added two players in pre-season and it will be down to them to win their place in the team. I cannot say more than that.
"Jay Emmanuel-Thomas was not very sharp today because he was sick yesterday, but he has some great qualities as well. Theo is sharp physically, he has worked very hard and he is ready to start the season."