Damien Comer or Shane Walsh? Brendan McCole's chosen assignment key for Donegal

Before the ball is even thrown in this afternoon, we will find out who Jim McGuinness considers to be Galway's biggest scoring threat - Damien Comer or Shane Walsh.

So far this year, Donegal full-back Brendan McCole has been his team's dedicated man-marker - conceding just nine points from play or marks in seven matches.

In those encounters he has faced Darragh Canavan twice, holding him scoreless from play in their most recent meeting and without a touch in extra-time in the Ulster semi-final. He held Shane McGuigan scoreless for 70 minutes until he kicked over two points in injury time as McCole dropped back to deny any late goal chance.

He has also marked a roving Sam Mulroy, Andrew Murnin and then Conor Turbitt against Armagh, conceding just 0-01 on each of the Orchard forwards and 0-02 off the Louth marksman. Brian Hurley was also kept scoreless while on him during the first half against Cork, and Clare's Aaron Griffin, who slotted 1-08 in his other four championship games, didn't get a shot away before being replaced in their match-up.

McGuinness' Donegal team go forward and defend as a unit, with a backline made up of an attack-minded half-backs, and converted midfielders or half-forwards. Together the six named starters have scored 2-33 from play in five games with Donegal defenders as a collective accounting for over a third of their team's total from play and an impressive average of 0-06 per game.

At the other end, they swarm numbers around the danger zones with McCole -who is the lowest scoring of the six starting backs with just one point thus far - set to again be the only out-and-out defender to begin the game for the Ulster champions.

However against Galway the decision of who to assign him to could prove