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.
25. Michael Smith (signed from Swindon Town)
Signed for Pompey permanently in 2016 after a successful loan spell. Played 37 times for the club before joining Northampton Town on loan, and then Bury on a two-year deal. Last season he played for Rotherham in the Championship. Photo: Joe Pepler
26. Adam Buxton (signed from Accrington Stanley)
Failed to make a league appearance during his time at Pompey. Signed in August 2016 but was at National League side Tranmere Rovers by February. In June he joined Morecambe on a one-year deal. Photo: Colin Farmery
27. Liam O'Brien (signed from Dagenham & Redbridge)
Began his professional career at Pompey and rejoined them in 2016. Made three appearances in the Checkatrade Trophy in 2016/17 before joining Coventry City. Photo: Joe Pepler
28. Stanley Aborah
Joined Pompey after his contract ended at Notts County. Released by the Blues after just four appearances - three as a sub - and last played for Waterford. Photo: Joe Pepler