Munster prop Federico Pucciariello and recently departed Ulster second row Justin Harrison have been named in the Barbarians squad along with former Leinster prop Ollie le Roux.
Pucciarello, Harrison and le Roux are part of a 30-man squad that will take on Ireland, Belgium and England.
England internationals Iain Balshaw and Lesley Vainikolo are also named in the squad after being overlooked for their country's two-Test New Zealand tour next month.
The Baa-baas have named a squad that includes former Australia Test fly-half Stephen Larkham and ex-Wales captain Gareth Thomas.
Larkham is part of a sizeable overseas contingent, with fellow Australians Morgan Turinui and David Croft also selected, while London Irish provide their Australian full-back Peter Hewat and Samoan centre Seilala Mapusua.
Elsewhere, Newcastle-bound Otago captain Craig Newby will fly the New Zealand flag along with Saracens fly-half Glen Jackson.
The squad, coached by Cardiff Blues boss David Young, tackle Belgium in Brussels on Saturday, before facing Ireland on 27 May and then England.
Barbarians president Micky Steele-Bodger said: 'Like England and Ireland, we have had to cut our selection cloth in line with the European commitments of other clubs this weekend.
'However, we are delighted that players from Bath and Worcester, for instance, will be joining us in time for the second and third fixtures.
'Indeed, we are most appreciative of the co-operation we have received from a host of clubs across the board in making players available this year.'
Barbarians squad:
Backs - I Balshaw, P Hewat, T Delport, L Vainikolo, G Thomas, M Turinui, J Pretorius, S Mapusua, T Smith, S Larkham, G Jackson, A Gomarsall, M Claassens, R Powell
Forwards - F Pucciarello, C Visagie, O le Roux, P Collazo, D Crompton, M Regan, S Bruno, J Harrison, K Chesney, D Grewcock, R Skeate, P Wannenburg, M Molitika, D Croft, M Chapman, C Newby
