A bunch of numbers are swirling around the head of Jonathan Walters this week, the start of a very big few days for the Republic of Ireland team.
Where are we with Walters? Well, 34 is the age that he will be by the end of this month; 50 is the tally of caps he will be on should be play in Saturday's World Cup tie in Tbilisi; second is his ranking in terms of goal scorers in this Robbie Keane-free Ireland squad; 100% is the time spent by Walters on the field in Ireland' s six-game campaign in the World Cup to date.
And then we have 90: the number of minutes which the forward managed to play over four games at Euro 2016. Walters' fitness was a big concern for the Ireland boss in the build-up to the tournament in France, it dogged the side once the whistle started in that opening game, against Sweden, when a clearly-unfit Walters lasted just over an hour before he was replaced, only to be seen again in the closing moments of the defeat to France.
Martin O'Neill has had a relatively stress-free week in the build up to today's flight east to Georgia. No squad squabbles, no late-night departures from the camp to complete a transfer. Not much for the manager to complain about.
Bar the long-term absentee Seamus Coleman, the only major injury is Jeff Hendrick, and while he is a player valued by O'Neill, his off-colour display in the last qualifier, and an indifferent start to the season with his club, placed Hendrick's position in the team in jeopardy anyway.
But there was one big worry for the Ireland boss. Jon Walters.
He's a 33-year-old man with a beard, so is he really The Messiah when it comes to Ireland and the World Cup?
It looks that way, in O'Neill's mind. Walters is one player who is key to the team shape for this Ireland boss, and that's why O'Neill has stated again and again this week that he is not too stressed about Walters' fitness. Getting him to Dublin, even though he didn't play for his club last weekend, was one plus. Getting him out on the training pitch, even for limited work with the physio, was another boost.
But O'Neill has a big, big call to make for his team for Saturday: to play Walters, a player soon to be 34 who suffered a nasty injury while on club duty less than two weeks ago, who struggled with injury before and during Euro 2016, or to leave him out.
Managers are often faced with these big decisions. It's how they earn their corn. We often learn a lot about the manager, and a player, by the decisions those managers make.
Jack Charlton and Ronnie Whelan were at odds over the player's fitness and ability to play at the 1990 World Cup finals. Jack won that round.
Jack again took a big risk in pitching Phil Babb in for his competitive debut on the World Cup stage against Italy in 1994. Babb didn't let him down.
In a revival of the Whelan story from '90, the last World Cup for Ireland saw Jason McAteer so determined to play that he would hide as much as possible his injury.
But O'Neill relies on Walters more than McCarthy or Charlton did on those players, which is why the Derry native will give Walters as much time, as much leeway, as possible. It's what you do with your top players.
"I know the knock he got (with Burnley) was pretty bad but sometimes these bad ankle injuries do settle down pretty quickly. And, yeah, I think Jon is the type of character if he's 50-50 or touch and go and Jon's on the plane, you know he's available for selection," Roy Keane said earlier this week.
"Would the manager take the chance, even if he didn't train all week, to play him on Saturday? That's an option, yeah. It's not ideal but once Jon is on that plane I'd be pretty confident that he'll be available for selection."
A lesser player may have shirked international duty this week: Walters is still settling in at a club who paid a lot of money to sign him in the summer, he suffered a genuine injury while playing for his club last week.
Certain Ireland players - some of them are in this squad by the way - decide how injured they are are and don't show up in Dublin if carrying a knock.
Walters? He's made from different stuff.
"That would never have crossed our minds with Jon," Keane said when asked if Walters might have sat out this Ireland trip to get himself fully fit - a reasonable position to take in an age where someone like Scott Hogan needs to take two years to decide if he's fully recovered from an injury before he deigns to declare himself for Ireland.
"Jon's had a good move, he's had a pretty decent career, he's been a big player for us, a big character for Ireland, certainly over the last two or three years, whether it be in the dressing room, set-pieces, on the pitch."
It's amazing to think that a player, who a decade ago was playing in England's lowest division and who only made his international debut at the age of 27, is on the verge of winning his 50th cap.
That used to be a big deal as 50 caps was enough, in the past, to earn you a testimonial.
Walters won't get a testimonial. No one will, those days thankfully in the past.
But the veteran deserves every chance to make himself ready for Ireland, for Martin O'Neill and Roy Keane, for Saturday's game.
O'Neill could of course take the cautious route, not take a chance on Walters on Saturday to keep him fit for Tuesday's tussle with Serbia in Dublin. But that's a horse of a different shade.
Serbia at home will be a test of skill and talent, Ireland trying to find a way past the pass-masters in the Serbian side which, as of now, tops the Group D table.
But Georgia away is a battle. Always has been, back to the Brian Kerr era when the side had to really graft and, in a very hostile atmosphere, grind out a hard-fought 2-1 win.
The 2-1 win in Tbilisi in 2014, when the tie was won by a moment of magic from Aiden McGeady, was overall a victory built on a foundation of sweat and tears.
O'Neill risked Walters in Paris last year and it backfired, on both parties, as the player was unable to contribute fully on the day, or in the rest of the campaign.
Starting Walters on Saturday is also a risk but this veteran, the only outfield player to have played in every minute of every game in the campaign, deserves the chance.