Sim. Quando você retornar aos Estados Unidos, o oficial de fronteira poderá, e provavelmente o readmitirá, durante sua estadia original de 90 dias:
Trips to Canada, Mexico, or nearby Islands
If you are admitted to the United States under the VWP, you may take a short trip to Canada, Mexico, or a nearby island and generally be readmitted to the United States under the VWP for the remainder of the original 90 days granted upon your initial arrival in the United States. Therefore, the length of time of your total stay, including the short trip, must be 90 days or less. Citizens of VWP countries* who reside in Mexico, Canada, or a nearby island are generally exempted from the requirement to show onward travel to another country* when entering the United States.
Fonte: link
Isso é feito para evitar que as pessoas usem "tiragens de visto" para países vizinhos, como forma de permanecer nos EUA indefinidamente com o VWP.