Kanu will miss the start of Pompey’s pre-season while he undergoes heart tests.
The veteran striker has a routine heart appointment in Nigeria next week.
It is standard procedure as doctors continue to monitor his condition following a successful operation to replace an aortic valve in November 1996.
As a result, the striker will be absent from Friday’s return to training at the Wellington Sports Ground.
Instead, Kanu will be back a week later on Friday, July 8 – along with Liam Lawrence and Tal Ben Haim.
Lawrence and Ben Haim have been given an additional week off after playing international football this summer.
At this moment in time, that will leave just eight players present on Friday, including new signings David Norris and Jason Pearce.
Meanwhile, Hermann Hreidarsson has still to agree terms and is not yet expected to be in attendance.
Blues manager Steve Cotterill said: ‘Liam, Kanu and Ben Haim won’t be there for the first day and with Hermann, it depends what he decides to do with his contract.
‘They will be back in a week later on July 8, though.
‘Kanu has got a little bit longer because he has a heart appointment.
‘He is fine. It’s just a normal check up but he’s got an appointment he needs to have out of the country.
‘His health is fine, there is no problem with that.’
Friday signals the first of two days that Pompey’s players will be assessed by the medical team.
Each player will arrive at set times to undergo a variety of tests to assess their fitness levels and other aspects.
Full training will then begin on Monday, when the squad will come together for the first time.