After the emergence last season of a historic number of Americans emerging into the top 50 of the ATP Rankings, many have dealt with injuries since including Sebastian Korda and Brandon Nakashima.
Korda in particular has been due back since Estoril but has now withdrawn from Barcelona Open Banc Sabadell next week further postponing his return to action.
While for Nakashima, he will rest with a knee injury blighting his progress and has pulled out of both Barcelona and Madrid 'in order to get back to 100%'.
This leaves the likes of Taylor Fritz, Frances Tiafoe and Tommy Paul to fly the American flag with Jenson Brooksby also out injured indefinitely.