Meanwhile, West Ham have been busy strengthening their options out wide, with Andriy Yarmolenko and Felipe Anderson arriving and set to arrive respectively, in deals reportedly worth around £70 million combined.
That should increase the likelihood of Thomas remaining at Derby, whose desire to keep the 19-year-old should also increase after Saturday's 4-1 friendly win against Notts County.
Thomas was heavily involved at Meadow Lane, scoring twice in 45-minute cameo for the side now managed by the former West Ham midfielder Frank Lampard.
And on that evidence, the Gloucestershire native can expect to add to his two competitive appearances when the new campaign begins.
With Derby, not West Ham.