Analysts believe the 65-strong chain is unlikely to form part of Whitbread's long-term plans.
Whitbread said the chain was subject to the same reviews and performance targets as its other brands and it would take another look at it if it did not come up to scratch.
The chain is thought to be a "perfect fit" for Gioma's Gaucho Grills.
Gioma has previously admitted Germany would be a logical next step after buying 23 outlets in The Netherlands and Switzerland 17 months ago.
Gioma said it was "open minded" about acquisitions.
The speculation came as Gioma reported annual pretax profits up from £800,000 to £2.6m on turnover up from £7.8m to £24.3m..