The Scottish international made his comeback for the reserves against Arsenal on Monday - his first competitive game of the season. He fractured his thumb in a training ground drill with coach Hans Segers in the opening weeks of the campaign.
He is now fit and raring to go and is, naturally, desperate to return to first team action.
However, the form of Kasey Keller this season makes this anything but a formality and Sully is well aware of the challenge ahead.
"Of course, he's done brilliantly and it is going to be tough," reflected the former Wimbledon player. "But I want to be playing first team football - that's the bottom line.
"The only way you can do that is to work hard and do well in games when you are playing.
"You're waiting for the manager to pick you, it's not my decision and you've got to be ready for when you're called upon."
Whereas formations and tactics can be tinkered with to accommodate outfield players, there is no such allowance ever afforded to goalkeepers. It is not, as a rule, a rotational position and when one keeper has the shirt the other is invariably left frustrated.
"You're either in or out. With the rest you can tinker with it a bit and play players out of position if neccessary, but with keepers, like I say, you're either in or out.
"I keep going on, but the only way you can do it is to work hard and try and impress."
Sully also faces a challenge on the international front to win back his Scotland place and take part in the remaining Euro 2004 qualifiers.
"That's another thing to look forward to," he added. The reserve game was the first step and, what's come out of it is that a lot of things are not too bad.
"There are one or two things that need a bit of work and you've got to play games to make decisions. To be honest, technically I feel fine, it is decision making that only comes with playing games.
"You can get a million balls smashed at you in training, but it is not the same as when there are bodies flying around and all that. You've got to make choices and that only comes with playing games."
Neil Sullivan accepts that he faces a great challenge to dislodge Kasey Keller from the No.1 goalkeeping spot following his return from injury.