Ross Barkley misses the trip to Tanzania with a groin problem
The Blues take on Gor Mahia in their first pre-season workout and Wayne Rooney will be the headline name in the party as he begins his second spell with Everton.
While Barkley has remained behind on Merseyside because of an apparent groin injury, goalkeeper Robles has reportedly been omitted because he is expected to transfer away from the club this summer.
Despite being given a squad number yesterday, the Spaniard feels his days are numbered at Goodison Park and he has been linked with a move back to Spain or one of the newly-promoted Premier League sides.
Yannick Bolasie accompanies the squad, no doubt in an ambassadorial role on his home continent, while he continues his rehabilitation from double knee surgery but Ramiro Funes Mori also remains on Merseyside as he makes his way back from a knee operation of his own.
Full squad: Maarten Stekelenburg, Mateusz Hewelt, Chris Renshaw, Tom Davies, Phil Jagielka, Ashley Williams, Callum Connolly, Jonjoe Kenny, Michael Keane, Muhamed Besic, Leighton Baines, Morgan Schneiderlin, James McCarthy, Davy Klaassen, Gareth Barry, Idrissa Gana Gueye, Joe Williams, Kieran Dowell, Kevin Mirallas, Wayne Rooney, Aaron Lennon, Dominic Calvert-Lewin, Ademola Lookman, Matthew Pennington, Yannick Bolasie.