One of the big question marks for All-Ireland champions Dublin heading into the summer has been their full-back line.

As far back as the 2016 All-Ireland semi-final, when Paul Geaney put pressure on Stephen Cluxton under a high ball to force a Kerry goal, teams have been targeting that area of the park as one where they might get some loose change.

Last summer, Wicklow repeated the trick when James Stafford punched to the net in the Leinster quarter-final at Portlaoise.

Laois stuck Donie Kingston on the edge of the square in the Leinster final, while Galway struck a first-half goal through Damien Comer in the All-Ireland semi-final when he rose highest to beat a couple of Dublin backs to the ball.

Without labouring the point, Tyrone had their lessons learned when they earned a late penalty in last year’s final. Philly McMahon brought down Colm Cavanagh, again after a high ball had been launched in on top of him from out the field, and Peter Harte buried the spot kick to the net.

So if Dublin are to create history in September, it’s an area that arguably needs work. Cue the return of three-time All-Ireland winner Rory O’Carroll.

After a couple of impressive performances for his club Kilmacud Crokes in the Dublin Championship, Jim Gavin confirmed that the full-back was training once more with the panel, having last played back in 2015.

"He's been going great," said James McCarthy today at an AIB GAA event.

"I obviously played against Rory in the club championship game against Kilmacud and he was good against us that night.

"He'll add greatly to our already great set of backs. The competition has ramped up altogether now again.

"Lads have a lot of respect for him, he's a great character and he's a strong-willed man. He was obviously a very important player for us before he went away.

"He's come back now, he's excited to be back and he has a huge challenge to compete for a place on the team. Lads were delighted to have him back."

Three years is a long time to be out of top-level sport, but McCarthy says O’Carroll played some sport during his time in New Zealand.

One player who McCarthy was giving a little bit less away about was Diarmuid Connolly. The Vincents clubman also performed well in recent Dublin club games, although in an apparently deeper role than followers of the game would be used to seeing him play.

Whether he’s back training, McCarthy was certainly less positive than he had been about O’Carroll, choosing instead to tow the party line.

"Jim has an open door policy," confirmed McCarthy.

"Diarmuid is a great player, be great to have him back.

"You've just got to respect the decision there but it's always an open door policy there. You'll have to ask Jim that."

We’ll have to wait and see, with Dublin set to play Louth in two weeks after their win over Wexford on Sunday.