James Coppinger felt the time was right for Pompey forward John Marquis to leave Doncaster in the summer.
The London-born striker sealed a switch to Fratton Park in July for a fee which could rise to £2m.
Marquis joined Pompey for a second time on the back of a prolific three-season spell in front of goal at Donny.
The 27-year-old struck 67 times in 153 appearances during his spell at the Keepmoat Stadium.
Coppinger was a team-mate of Marquis’ at Doncaster and felt he was the ‘perfect fit’ for the club.
The Donny midfielder lauded the striker’s ‘high standards’ and how he demanded the best from everyone.
But Coppinger admitted the time was right for Marquis to make a move away in the summer.
The former team-mates are now set to meet for the first time as Pompey travel to Doncaster on Saturday.
And Coppinger is hoping they can keep the marksman quiet.
He told The Sheffield Star: ‘John needed to leave.
‘I think the time was right, he’d done fantastic for this club.
‘When we signed him in League Two, he was the perfect fit.
‘We needed someone like him who would score goals and demand every day.
‘His standards were really high and he demanded off everyone.
‘For the last two or three seasons he was outstanding.
‘The timing was right, he’s left.
‘It’ll be interesting to pit our wits against him.
‘We’ll be looking forward to it.
‘Hopefully he won’t score and we'll put in a good performance.’
Donny manager and former Pompey defender Darren Moore only worked with Marquis for a short period in the summer.
He was named Doncaster boss just a few weeks before the 27-year-old rejoined the Blues.
Since moving back to Fratton Park, Marquis has netted two goals in 12 appearances.
But Moore is aware of the threat Marquis will pose his troops on his return to the Keepmoat.
‘John put a lot of demands on himself at the very highest level to want to score goals and believe that he could score goals in every single game,’ Moore said.
‘While ever the individual has got that you can't knock it out of them. You want to keep that in them.
‘He’s got that wonderful desire. He eats, sleeps and breathes the game. He wants the best and to do the best in the game.
‘We wish him well. He's gone on and moved on after he's done the job what he needed to do here.
‘We prepare, if he should play on Saturday, and we know the threat he carries.'