Date of birth
The Coventry striker made a loan switch to Pompey for the remainder of the season in January 2022.
He is linking up with Blues boss Danny Cowley again, with the pair previously working together at Lincoln.
He netted 16 goals in 34 appearances during an impressive spell with the Imps, which followed another prolific stint at Mansfield.
Walker – who has represented England up to under-20 level – began his career with Nottingham Forest.
He gained experience with brief loan spells at Burton, Stevenage, Port Vale and Bolton before being sent to Mansfield for the 2018/19 campaign.
It proved be a successful season for Walker, who struck 26 goals in 52 games and was named in the League Two ‘Team of the Year’ as the Stags narrowly missed out on promotion into the third tier.
Lincoln was his next stop, although good form – which included a run of six strikes in five matches – at Sincil Bank saw the forward recalled early by Forest.
The son of former England international Des Walker, he made a permanent switch to Coventry in August 2020 and has found the net on 11 occasions for the Championship outfit.