The poor performances have seen Arsene Wenger's position come under increasing scrutiny and led to some calling for a new man at the helm.
However, Walcott insists the poor start is the players' fault and not that of the Arsenal manager.
"The boss is a great man, he can deal with anything thrown at him," he told Absolute Radio's Rock 'n' Roll Football.
"He's been at the club for over 15 years and so he's not under any pressure at all.
"Us players, we need to look at ourselves and start doing it on the pitch, to be honest.
"A lot of people say about the defensive sort of issue but it's not just the back four, you need to look at defending as a whole team.
"We haven't managed to do that, to be honest, so we need to make sure we're at it against Bolton at the weekend.
"It's going to be a tough game. They have come from a good result during midweek.
"We've got our home fans as well. We've got a few home games and that's important for us now, to have our home support.
"The boss can deal with anything."