Notts County’s assistant manager suffered National League play-off defeat to Grimsby last week in a dramatic 2-1 extra-time loss.
Grimsby, who have the Irishman’s former Pompey room-mate and travelling companion Ben Davies on their coaching staff, will now meet Solihull Moors in the play-off final on June 5.
In the meantime, Magpies boss Ian Burchnall has since quit to become head coach of Forest Green Rovers and fulfil his Football League ambition.
He replaces Rob Edwards at the helm of the League Two title winners, following his post-season departure for Watford.
In turn, right-hand man Doyle is expected to follow Burchnall to the New Lawn, renewing their Notts County partnership.
The former Pompey skipper hung up his boots last summer to focus on his coaching passion, although remained registered as a player with the Magpies should an emergency arise.
Should he also depart for Forest Green, that will set up a Fratton Park reunion at some point, with Rovers now occupying the same division as the Blues.
Doyle’s final Pompey appearance was in the May 2017 triumph over Cheltenham, with the 6-1 success earning the League Two title on the final day of the 2016-17 season.
He subsequently moved to Coventry following 97 appearances and three goals after growing concerned over the lack of a new Blues deal.
Although he has never played at Fratton Park since, he did attend the May 2019 play-off second-leg clash with Sunderland as the club’s guest.
He was also back on the south coast in November at the Better Late Than Never book launch for Played Up Pompey Three and Pompey: The Island City With A Football Club For A Heart.
Doyle remains a hugely popular figure among the Fratton faithful and retains a strong affection for the club he skippered to promotion to League One.
The 40-year-old’s appointment at Forest Green is widely anticipated to be completed this week as Burchnall sets about his challenge.
Danny Cowley’s side will discover their schedule on Thursday, June 23, when League One fixtures are released.
Pompey return for pre-season training on June 20, with their League One campaign kicking off on July 30.
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