City suffered their first loss at Treyew Road since October when they went down to Hayes & Yeading in Vanarama National League South and Tully said: “We need consistency in this league if we are going to do well. On Tuesday night we got what we deserved because we weren’t ruthless enough and they were.
“People are playing for places and that’s the biggest thing I’ve said to them. We’ve only got 16 in the squad, but if they aren’t doing it I will get people in who can do it.
“There are players on the bench who want to start and I will make changes if we need to.”
Tully is still hoping to sign a new forward in time for Saturday’s home game against early-season leaders Concord Rangers.
He added: “We’re still making a few phone calls and hopefully we’ll be able to get someone in before the weekend. We need goals - that’s where we’re weak.”