With the Scottish Premiership season just around the corner and players getting their match fitness up, there's no doubt every member of every squad is going to have a part to play this campaign.
The way the season is structured means it will be more condensed than ever and will be all about who's got the strength in depth to cope with the demands for success.
Celtic and Rangers have bigger player pools than the rest of the league due to their financial muscle but it will also be a test for the big two.
Both sides are well into their preparations but having watched them closely over the past week or so, I can't help but think fringe players putting pressure on the first-choice stars will be a must for Neil Lennon and Steven Gerrard.
Barring a position or two, most people can pick the first-choice teams of Lennon and Gerrard and that will only change if the players in reserve can make an impact.
There are still question marks for both Old Firm managers, though, when you look beyond the regular starters.
For Lennon, it's clear he needs another first-team goalkeeper. Scott Bain is his only senior keeper and after losing Fraser Forster and Craig Gordon in the summer, the Ulsterman will be desperate to get competition for that No.1 jersey.
Neil will look at his main outfield players and be content but there's concerns about the fitness of a few. Young Mikey Johnson is going to be a wonderful player but is still missing with a knee injury. He can't seem to get an injury-free run, which will be frustrating him.
Leigh Griffiths' fitness issues have been well publicised and Tom Rogic is another who can't seem to get to the levels everyone knows he can reach.
With Jozo Simunovic also leaving in the summer, it leaves Celtic a bit light in central defence. Hatem Abed Elhamed is flexible because he can play all across the back four but he's a doubt for the start of the new season after getting injured in France.
Throw in the possibility a big bid could come in for top scorer Odsonne Edouard and that would really upset Celtic with such a big season on the horizon.
So when you put all that together, Lennon has to, as ever, rely on his ever-present stars like Callum McGregor, Ryan Christie and James Forrest to stay clear of injury.
On the other side of the city, Rangers have played three and won three in pre-season without conceding a goal.
In the past, however, they've got carried away at times and not been able to back up their optimism so they need to show they have learned from that.
Like Lennon, Gerrard will be happy with his core 13-14 players who he knows he can rely on, but others must be ready to step up.
Brandon Barker has caught the eye with a couple of cameo appearances in pre-season and has utilised his blistering pace to hurt the opposition. Can he do it over a sustained period? That's up for debate.
Jermain Defoe limped out of a game against Motherwell on Wednesday night, leaving just Alfredo Morelos as the sole striker. Reinforcements may well have to be brought in as a matter of urgency.
I've spoken previously about Rangers having only two fit centre-halves, Conor Goldson and George Edmundson - although that has changed now Leon Balogun has signed. Filip Helander is a worry as he's not featured all pre-season and Nikola Katic is injured.
When you consider both second-choice full-backs - Nathan Patterson and Calvin Bassey - are very inexperienced, it's a risky situation for Gerrard considering how big a season it is.
So as much as the first-choice stars will have an important part to play, it could be the squad players who give their team the impetus when needed.