As a free agent, Ryan Tunnicliffe wasn't short of options to remain in the Championship, with Luton also tabling him a deal to extend his stay.
Yet the midfielder opted to drop down to League One and sign up for Danny Cowley's Pompey's project.
That might not have come to fruition, though, if it hadn't been for the Blues also prising Shaun Williams to the south coast.
The pair not only played with each other at Millwall but are close mates off the pitch.
So much so that they had been keeping up their fitness levels together over the summer break.
It was during one of those runs when Williams and Tunnicliffe both found out the Blues were interested.
And Williams believes it was on the back of that conversation that Manchester United youth product was persuaded to Pompey.
The Irishman said: ‘We've been running together the past couple of weeks. We run together trying to keep fit over the summer.
‘I told him that I had a bit of interest from Portsmouth and he said: "I think I might have a bit of interest from them as well".
‘When I was here meeting with the manager, I told him that I've let Tunny know I was coming.
‘Tunny was like: “Wow, if we can get the deal right then I'll come as well”.
‘Tunny is more of a box-to-box midfielder. He is deceptively fast and has got a serious engine on him.
‘He can also play and can hopefully bring goals to his game and fire in a few throughout the season.
‘We played quite a bit together at Millwall. He's a really good player and I enjoy playing alongside him.
‘He was another one who had options so Danny must have sold the club to him. Luckily enough, he is here now.’
Tunnicliffe, who penned a two-year deal at Pompey with the club option of an additional 12 months, linked up with his new team-mates for pre-season training on Wednesday.
He was given the opening two days off for his wedding.