JIM DUFFY has been given a selection boost ahead of Morton's Scottish Cup clash with Airdrie tomorrow after Rangers granted them permission to field loan star Robbie Crawford.

The midfielder moved to Cappielow on a temporary basis earlier this season and will remain in Greenock until January.

Ally McCoist's side will kick off their bid for cup glory against Dumbarton while the Ton are in action against the Diamonds and the Gers have decided they won't require Crawford's services should they advance to the latter stages of the competition.

However, Duffy will not be able to play striker Declan McManus after parent club Aberdeen refused to allow him to become cup-tied in the third round.

"Rangers have given us permission to play Robbie," said Duffy.

"They have a lot of options in the middle of the pitch and decided that he can play. It is good that Robbie is available.

"I anticipated that Declan wouldn't be available, we had a similar situation in the League Cup earlier in the season.

"We respect the decisions of both clubs and I can only focus on the players that I have available for a game that we are all looking forward to."

The visit of their League One counterparts tomorrow gives Morton a real chance of booking a place in the fourth round.

The Diamonds were defeated 2-1 when they made the trip to Greenock on league duty earlier in the season and the pair will square off again in a fortnight.

Duffy said: "When you play someone in the same division as you in the cups there is always that familiarity.

"But Airdrie have certainly improved in recent weeks since the last time we played them so it will be a very tough match for us.

"They have had a couple of results and will have a bit of confidence about them.

"They are a side who can give you problems, they are very competitive and have good players.

"They are a very capable team that score goals so we will have to be at our best to get a result."