The 19-year-old, who was recently included in the Scotland Under-21 squad, was sent for a precautionary scan this morning and, when the results came back, they weren’t positive.

“Charlie has torn a cartilage and will be out for the next month,” said Craig.

It’s another blow for the United boss, who suffered a broken ankle on his first game in charge against Aberdeen, then lost the services of Jim McIntyre for the remainder of the season due to a back problem.

Mulgrew’s injury not only leaves the Tangerines desperately short of left-sided players but it also denies them the services of a young man whose form has been impressive since switching to Tannadice in the January transfer window.

Also missing from the United squad that will head to East End Park to face Dunfermline on Saturday will be defender David McCracken, who is suspended.

On the plus side, Barry Robson has now served his ban and will be included, while there could be a starting role for Lee Mair, especially if the former Dundee man comes through today’s reserve clash against Inverness Caley at Station Park, Forfar.

Out for more than a year with a knee injury, Mair has battled his way back and came on as a substitute for the last half-hour against ICT at the weekend.

Another run-out for the second string today will see his fitness improved further and, with the Tangerines’ rearguard looking less than impressive as they lost four goals to the Highlanders at the weekend, Mair could be set for a start at Dunfermline on Saturday.

“Lee has worked his socks off to get himself back into the squad,” said Craig. “He’s already had half-an-hour in the first team on Saturday and today’s reserve game will help him improve on his match fitness.”

Paul Ritchie still remains some way off a top-team place.

“Paul has been back training in the gym, but it’s nothing too hard at the moment,” added Craig.

However, fears Jack, who has only recently returned to first-team action after a lengthy spell out, could be set for another stint on the sidelines, appear to have eased.

In fact, there is every possibility the big goalie could retain his place on the synthetic surface at New Douglas Park.

“Kelvin’s injury isn’t as bad as we first thought and it will be a case of monitoring him over the next few days,” said boss Alan Kernaghan today.

Skipper Barry Smith and young midfielder Kevin McDonald also picked up knocks against the Bully Wee, but are likely to be available for the cup-tie.

Tonight, meanwhile, the Dark Blues meet Montrose in a closed-door game and set to feature is left-sided midfielder Steven Robb, who has been out recently due to illness.

Also due to take part is Lee Wilkie, who continues to build up his match fitness.

“Lee is getting better all the time, but he has still to get 90 minutes under his belt,” stressed Alan.

The Dens gaffer expressed delight at the fact Dundee have sold out their allocation of tickets for the trip to Hamilton.

“It’s great to know we will have a big following and, hopefully, we can go down there and do well for ourselves and the fans.”

Meanwhile, long-term injury casualties Ryan McCann, Steven Milne and Peter MacDonald are continuing their progress.

Darren Sheridan missed the Hamilton win due to flu, but should be OK to face Airdrie United a week on Saturday.

However, Burgess warned against complacency, stressing there are no easy ties at this stage of the competition.

“Obviously, first and foremost we are delighted it’s a home draw. We’ll be favourites to win, but I’m sure that would have been the case with whoever we pulled out,” said Keith.

“Clydebank have already beaten Bonnyrigg this season and they, in turn, have beaten us, so that should be a big enough warning that we will be facing a decent side.

“In any case, you can be lucky in possibly one ore two games, but you don’t get this far in the competition on luck alone, so we’ll have to be on our guard.”

Dave Baikie’s Bo’ness are at home to Auchinleck Talbot, while Bathgate, conquerors of Lochee United in the last round, will entertain Beith. The final tie sees Petershill play host to Irvine Meadow. Ties are due to go ahead on Saturday, March 11.