Assistant manager Mickey Lewis joked he might need to be named on the bench, but the mounting injury worries are no laughing matter.
No fewer than 11 first-team players are either ruled out or have question marks over their availability ahead of the trip to north Wales.
“I’ve been doing a bit of running, so I will see if I can get myself on the bench,” Lewis said.
“We will regroup and see how many players we have got available.”
An already dire situation grew worse this week, with centre backs Michael Raynes and Johnny Mullins picking up knocks ahead of Thursday’s first round replay at Gateshead.
During the course of their battling 1-0 win, which came after extra time, Danny Rose and Dave Kitson were forced off.
It meant United finished the game with six players on the pitch aged 20 or under.
The youngsters will be needed again against Wrexham, although there is hope at least some of those struggling can play.
Kitson appeared to only have cramp, while Lewis was relatively optimistic over Rose and did not think the centre backs had serious problems.
He said: “Hopefully the two centre backs will not be out for too long.
“Mulls did his knee on Saturday and played through it until the end. I don’t think it’s too bad, he has had a scan, but we don’t know the full extent yet.
“Raynesy picked up a hip injury in training on Wednesday and we’ll look at it once we get back in.
“With Danny (a hamstring) was tightening up and hopefully him coming off saved it from being worse than it is.”
Jake Wright and Sean Rigg, both scheduled to return next Saturday, may be looked at to see if they can bolster the squad.
United are also checking to see if Asa Hall can play.
The on-loan midfielder was not permitted to feature by parent club Shrewsbury, but as the Sky Bet League One side have been knocked out it could clear the way.
While United were counting the cost on the pitch, Thursday’s win delivered a financial windfall.
They will receive £90,000 in prize money and television revenue, as Monday’s game will be screened live on BT Sport.
With the cash generated from the Gateshead game being televised, the cup run has been worth more than £120,000 to the club so far.
They will also head to Wrexham knowing who awaits the winners.
With the tie being played on Monday, both teams are in tomorrow’s third round draw, where the Premier League sides enter the fray.
They will be ball number 59 and will discover their potential opponents shortly after 4pm.