Declan O’Sullivan’s inability to make the starting line-up totally changes the dynamic of this All-Ireland semi-final. Éamonn Fitzmaurice has made it very clear there is no room for sentiment in his Kerry team. Current form and full fitness are essential prerequisites for inclusion.

It’s apparent that O’Sullivan and Bryan Sheehan do not meet the second criteria. O’Sullivan may feature at some stage but his absence from the start is a huge loss, not only to Kerry’s forward line but across all areas of the field. A hamstring injury has meant restricted training since the Munster final so his influence has already been curbed.

What makes O’Sullivan so important is the way he settles younger players, brings them into the game and basically makes others play well. There is also his vast array of passing and phenomenal work rate. He is one of the great Kerry footballers.

With Colm Cooper long since ruled out for the season, Declan became the main orchestrator of the team’s play.

O’Sullivan’s inability to start against Mayo means Kerry now field a very inexperienced forward line. It places a huge reliance on James O’Donoghue to put in another All Star performance. I feel that won’t be possible. Mayo will target O’Donoghue. Keith Higgins will probably man mark him but there will be plenty of Mayo men nearby at all times.

Sweeper system

I think we’ll see their sweeper system employed much closer to the full back line to protect Ger Cafferkey and Higgins. That could be James Horan’s lesson from the Cork victory.

This means other Kerry forwards must increase their scoring rate. But they will have their own problems tracking Mayo’s marauding half backs. That will make it very difficult to support O’Donoghue.

That looks like the critical factor. The ripple effect of O’Sullivan’s benching ultimately limits Kerry’s scoring capacity.

Sheehan’s injury means that frees within his range, which are almost certain points when he’s taking them, are now dependant on three, possibly four players having a good day.

O’Donoghue is not a worry from the right hand side but Paul Geaney and Johnny Buckley are shooting from the left. It’s all a little hit and miss or dependent who finds his range in the warm-up. David Moran will probably take one or two from distance as well.

At this level, that won’t do at all. Sheehan could come on but I get the impression he might not.

I do, however, like the decision to pick Peter Crowley instead of Killian Young as it brings a much needed physicality to the Kerry defence. Mayo will consistently target the middle with runners. Galway midfielder Tom Flynn showed them exactly how to do it in the All-Ireland quarter-final when he charged through the heart of their defence for a goal into the Hill 16 end. Not a hand was laid on him.

Fitzmaurice is aware of that threat. Crowley and Aidan O’Mahony will be tasked with shoring up these raids. Young is not a stopper, he’s a ball player with a natural inclination to attack. Kerry need a physical presence in the centre of defence tomorrow.

Sometimes, when defending, man marking duties have to be shelved and someone must go cover the space. Crowley can be that man.

That also means David Moran and Anthony Maher dropping back to help out. We all know Donnchadh Walsh will cover every blade of grass in Croke Park. A fit Declan O’Sullivan would have done something similar.

The midfield area will be critical. I think both goalkeepers will kick long to ensure a traditional high-fielding battle for possession. Mayo have become masters at foraging for the breaking ball. Particularly the O’Shea brothers – Séamus and Aidan – allied superbly by both the half back and half forward lines.

Mayo have the edge here. Colm Boyle, Donal Vaughan and Tom Cunniffe all supply serious support.

Also, their tackling is so good Kerry must accurately utilise the kick pass when moving ball out of defence. This was another area where Declan O’Sullivan excelled.

It all comes back to experience. That Mayo half back line of Lee Keegan, Boyle and Cunniffe have it in spades whereas Michael Geaney and Johnny Buckley might be shocked by the intensity that awaits them.

Foregone conclusion

Not that it’s a foregone conclusion. Mayo rely too heavily on Cillian O’Connor to score from play and frees. He is being used as a target man but would be more effective running onto ball rather than having to secure so much possession for himself.

There is a lack of pace to their inside line. Andy Moran might be of better use off the bench as we saw against Roscommon.

But their hunger should see them through to another All-Ireland final.

It was evident in the way they closed out the game against Cork. There was a composure to them, especially when Keegan and Vaughan came forward to claim the late insurance points. That comes from experience.

Kerry’s experience is sitting on their bench. If they unload Darran O’Sullivan, Kieran Donaghy and maybe O’Sullivan and Bryan Sheehan for the final 20 minutes, anything is possible. If the game isn’t gone.

Barry John Keane and Kieran O’Leary can also bring a renewed scoring threat. It’s a 20-man game tomorrow. The pace of the conflict will ensure that.

Mayo don’t want last year’s quarter-final decimation of Donegal to be their peak performance of this era. Nor do they want it to come tomorrow. Without Declan O’Sullivan, they shouldn’t need it.