TIMING, they say, is everything. The timing to read the trajectory of a breaking ball and pounce. The timing to spy the smallest gap just as it opens and burst on through to the other side. The timing to pick your moment for that defence-splitting pass.
Or even the timing to avoid cruel injury at the very start of the championship.
The latter, of course, owes everything to the fickle hand of fate as opposed to footballing intuition. So you can't blame Cian O'Sullivan that a summer of rich promise has turned into a running battle for fitness.
Dublin have played four championship matches, including one bout of extra-time, so far this season. That amounts to exactly five hours of football, excluding injury-time. And Kilmacud's fleet-footed defender has spent just five minutes of that time on the Croke Park pitch.
O'Sullivan's full SFC debut against Wexford last month was barely under starting orders when he made a burst for his first ball and his hamstring snapped.
The ultimate hammer blow, so to speak, and in medical terms a pretty bad tear too: he was sidelined for the next five weeks and only came through his first full training session last Tuesday night.
This was not what the doctor ordered, for sure. O'Sullivan had seemingly made the Dublin No 6 jersey his own during the National League -- with his pace, tenacity and eye-catching ability to glide across the turf in possession -- only to be hamstrung when it mattered most.
"Really frustrating," he admitted at the launch of the new Ulster Bank GAA iPhone app this week. "Last year I had a similar problem throughout Leinster. And this year, to have a good run in the league, and then get injured in the first game ... I would have taken any other time of the year to get injured. This is just the worst time.
"Especially now that we're going through the qualifiers, playing week on week. I'm missing a lot of matches."
Last year's Dublin U21 captain had entered the Wexford game under something of an injury cloud, having suffered a "minor" hamstring strain two weeks prior to kick-off.
Yet the player points out that he felt fine beforehand: he had gone for his scan, taken 10 days off, came through an internal practice match the Tuesday before without any setbacks, trained again on the Thursday night.
In other words, it was all systems go ... and then disaster struck.
Even though he has now resumed training, O'Sullivan knows that tomorrow's fourth round qualifier against Louth has come too soon -- certainly for a starting recall and, speaking on Wednesday, he also sounded doubtful of seeing any gametime from the bench. Besides, one player's loss is another's gain, and Ger Brennan has stepped into the breach at centre-back.
Looking on from the sidelines, he believes his colleagues are slowly getting there after a fraught summer start.
"We went out of the Leinster championship in poor fashion," the Crokes man accepts.
"We picked ourselves up, played a little better against Tipp, and again against Armagh. So there seems to be an incremental increase in performance.
"Hopefully we can build on that again against Louth.
"We are a team in transition. There are a lot of new faces and it is going to take a bit of time. From that perspective maybe going through the qualifiers wasn't the worst thing, to get a few more games under our belt, and let the team gel a little more."
But what about all that chopping and changing in the half-back line -- is it all down to his enforced absence?
"That'd be nice to think!" he replies. "I honestly don't know. There's such competition for places around the middle third of the field. We do have a few lads who are quite flexible in certain positions -- David Henry can play anywhere, Bryan Cullen is comfortable in the half-backs and half-forwards."
O'Sullivan is more emphatic when assessing Dublin's next opponents, Louth.
"They're the real, they're the moral Leinster champions and they're going to be out to prove that this weekend," he asserts.
"We are very mindful of the fact that they're going to give 110 per cent this weekend -- they're going to have the whole country behind them really. And nothing less from us is going to be sufficient to beat them.
"Our work-rate has to match theirs really. They have proved throughout the O'Byrne Cup and throughout the championship thus far that they are a good side.
"They have very talented forwards, very capable midfielders and a half-back line who aren't afraid to get up the pitch and score. So, they are a force to be reckoned with."
More promisingly for Dublin, the mood has lifted in the wake of last weekend's three-point victory over Armagh. Time will tell if it constitutes a watershed in the development of Pat Gilroy's evolving team, but O'Sullivan repeats the new Sky Blue mantra about work-rate being the key.
"We turned over Armagh a lot," he points out, "and it was very evident from the substitutions that we had to make -- I think four or five lads had to come on -- because lads were just knackered.
"They had given 100 per cent and just couldn't go on. From the work-rate point of view, that's up there with what we're trying to achieve."
O'Sullivan continues: "There's obviously been a marked increase in morale. It was a tough blow against Meath.
"We had won the Leinster championship the last five years and possibly a bit of complacency crept in this year. Maybe it was just the kick we needed to bring us back to reality.
"We put in a very good performance against Armagh. They are a very hard team to break down defensively and we were very happy with how we closed out that game.
He signs off on a hopeful note: "Morale is up in the camp. It's good to get those wins under you belt -- it adds to inner confidence."