Matt Clarke is one of the first names on the Pompey team-sheet.
The centre-back has already passed 100 appearances for the club at the tender age of 21 and even worn the captain’s armband recently.
With recent changes in both shape and personnel, Clarke’s presence in defence is a reassuring constant.
And, ahead of Sunday’s televised clash with Oxford, he is happy to adapt to whatever changes are deemed necessary.
Clarke said: “I just have to keep my level of performance up and do as much I can, no matter how much things alter around me.
“You have relationships with players, but the team has chopped and changed a few times this season, so you always have to be ready.
"We’re all professional and know how to do our jobs, so whoever’s playing and whatever formation, we’ll just go about our business."
“It’s important to have competition in your squad because it’s no good if everyone’s comfortable with their place in the team. You want to be kept on your toes.
“Three at the back has come and gone this season. We felt it worked first half against Gillingham, but every game is different and it didn’t really suit playing Oldham.
“We’re all professional and know how to do our jobs, so whoever’s playing and whatever formation, we’ll just go about our business.
“When there is a switch you just need to make sure you all work well together in order to get the job done.”
Pompey will take on an Oxford side who have just appointed Karl Robinson as their new boss to try to halt a slide down the table.
Clarke said: “There’s usually that lift around the club when a new manager comes in, so we need to knock the wind out of that.
“We won’t be underestimating Oxford, though. We know they’ve been on a bad run, but are capable of beating anyone in this league.”