Full back Amitage, who was one of the stand out performers during England's recent autumn internationals, and second row Kennedy will feature for London Irish in the top-of-the-table encounter with Gloucester, while Tait will line up for Sale Sharks against Worcester.
There is no suggestion that the three players will be released from England duty for any longer than a week, with an RFU statement saying they had returned home 'in order to get more game time prior to the RBS 6 Nations'.
England EPS for Portuguese training camp
Forwards: Tim Payne (Wasps), Andrew Sheridan (Sale), Phil Vickery (Wasps), Julian White (Leicester), George Chuter (Leicester), Dylan Hartley (Northampton), Lee Mears (Bath), Steve Borthwick (Saracens), Tom Palmer (Wasps), Simon Shaw (Wasps), Steffon Armitage (London Irish), Tom Croft (Leicester), James Haskell (Wasps), Tom Rees (Wasps), Nick Easter (Harlequins), Luke Narraway (Gloucester).
Backs: Olly Morgan (Gloucester), Mark Cueto (Sale), Paul Sackey (Wasps), Ugo Monye (Harlequins), Jamie Noon (Newcastle), Mike Tindall (Gloucester), Riki Flutey (Wasps), Shane Geraghty (London Irish), Danny Cipriani (Wasps), Toby Flood (Leicester), Danny Care (Harlequins), Harry Ellis (Leicester), Ben Foden (Northampton).
Also training with the EPS: Matt Banahan (Bath), Ben Kay (Leicester), Michael Lipman (Bath), Joe Worsley (Wasps)