Worries are increasing that Nolan and Carroll will be seen as automatic selections the minute they are fit.
However, Downing believes if the current XI continue to play as they are, Sam Allardyce will not be able to make changes.
He told London 24: “Last season the team picked itself because of the numbers but that isn’t the case this time.
“Even if your form dipped last season you were still in the team.
“It may cause a headache for the manager but I am sure he will like it, he has options from the bench.
“Like you saw Morgan (Amalfitano) came on and got the winner, he has come here to play.
“Obviously Andy (Carroll) and Kev (Nolan) have to come back, but if we keep playing well the manager can’t really change the team.”