Reports have emerged that Stags boss Nigel Clough is keen to be reunited with the 30-year-old, whom he signed while manager of Derby.
The 3-0 loss – which saw former Blues defender Oli Hawkins sent off – means Field Mill will once again stage League Two next season.
Portsmouth transfer news: Blues receive bids for former Luton and Millwall midfielder
Transfer gossip: Portsmouth eye raids for ex-Chelsea man and Charlton Athletic's former Wigan Athletic midfielder
'Is proving one hell of a signing.... A real livewire' - Portsmouth match ratings from 2-0 win at Cheltenham
Former Portsmouth pair help Ipswich flex muscle as Norwich City man is slammed for conduct in Peterborough's Plymouth Argyle reverse
Cheltenham boss Wade Elliott praises experienced Portsmouth in 2-0 defeat at Whaddon Road
And there’s doubts whether Jacobs would be willing to drop down to that level as he contemplates his next move.
The forward is currently weighing up his options, which includes an incentive-based offer from the Blues that would top up a basic salary depending on how the former Wigan man performs.
Jacobs believes that is a reasonable basis on which a deal can be struck, allowing him to extend his two-year stay at Fratton Park.
Yet, while Pompey have agreed new terms with Sean Raggett and edge closer to announcing a fresh deal for Reeco Hackett, the winger’s next chapter in his career remains up in the air.
That’s led to increased speculation regarding his future, with Mansfield joining former club Northampton in registering their interest in the Pompey favourite.
In the meantime, Clough has spoken of his need to bring in 4-5 new recruits that will prove the difference next season.
Speaking to the Mansfield Chad, the Stags boss said he wanted to make inroads on those signings as soon as possible.
And part of that process will be making ‘chase-up calls’ to targets who had previously indicated that playing League Two football was not for them
Clough said: ‘We definitely need one in each department, depending on who stays and who goes.
‘We only need one defender. We are happy with our defensive options at the moment. Then a couple of midfielders and a couple of attackers – maybe one attacker outright and one who just plays off a little bit.
‘That will be the aim. If we can get five in those areas then we will be happy.
‘We have started talking to players – you have to put a couple of scenarios in place.
‘We have made some chase-up calls this morning.
‘Three or four of the players on the list have said they are only interested in League One which you can understand.
‘So we just need to find out if that is still a definite for them – a make or break.
‘Some people change their minds. They might not have had the offers that they'd hoped for. So that will be the first job.
‘Then we work back from our targets like that.’