He’s not the first to leave Fratton Park to join up with his former manager. We’ve had a look at what happened to all 28 permanent signings Cook made during his time in PO4.
17. Amine Linganzi (signed from Etoile Frejus Saint-Raphael)
Linganzi played for Congo four times before arriving at Fratton Park in 2016. After a year he packed his bags for Swindon Town and last played for Salford City, but left the club at the end of his deal this summer. | Freelance Photo: SCC
18. Drew Talbot (signed from Chesterfield)
Talbot's move to Pompey in 2016 reunited him with Cook, who had managed him at Chesterfield. He left the club by mutual consent in December 2017, resigned for Chesterfield and played for them until his retirement this summer. | Freelance Photo: PinPep Media / Joe Pepler
19. Matt Clarke (signed from Ipswich)
A modern day Pompey hero. After a loan spell at the Blues in 2015 he joined permanently and has been a mainstay at the heart of the defence. After 60 appearances last season he signed for Brighton. | Freelance Photo: Joe Pepler
20. Danny Rose (signed from Northampton Town)
Was a key member of the League Two-winning team in 2016/17. Broke his leg in a match against Northampton Town in December 2017 and struggled to get back into the team after his recovery. Joined Swindon in January. | JPIMedia Photo: -