They were denied the opportunity to witness what the winger had to offer after he was lured to Fratton Park from Barnsley on loan for the second half of the 2018-19 season.
And now it seems Blues supporters will remain in a state of wonderment as the 28-year-old prepares to make his first return to Fratton Park since that curious move during that term’s January transfer window.
The former Southampton trainee is expected to be in Trotters boss Ian Evatt’s starting XI for Saturday’s League One fixture.
It’s just Isgrove could very well line up at right-back for the visitors – denying Pompey fans the long-awaited chance to see why former boss Kenny Jackett wanted the forward as part of his group for that season’s promotion bid.
The player was one of six players drafted that winter to supplement a side that entered the new year top of the table.
Yet by the end of the season, all a frustrated Isgrove had to show for his time on the south coast was three unused substitute appearances – and no promotion medal as the Blues finished fourth and lost to Sunderland in the play-off semi-finals.
Since then, the winger has put his PO4 nightmare behind him and won consecutive League Two promotions with Swindon and Bolton respectively.
He’ll be looking for a third advancement with the Trotters as they look to return to the Championship for the first time since 2018-19.
But if he does, it could well be as a right-back after a successful run-out in the position against Gillingham on Saturday.
Evatt utilised Isgrove there after first-choice Gethin Jones was ruled out for the rest of the year with a fractured fibula.
And he claims Isgrove could have a ‘very good’ future in the position as he weighed up his options ahead of Saturday’s Fratton Park visit.
Evatt told the Manchester Evening News: ‘He’s a good player, Lloyd, and he’s a fantastic lad.
‘I asked him to do us a job (at Gillingham) and he did it to the best of his ability.
‘I think he can develop into a very good right-back, by the way.’