By Mark Lamport-Stokes

BETHESDA, Maryland (Reuters) - Robert Rock's preparations for this week's U.S. Open at Congressional Country Club have been hampered because of visa problems, causing him to miss Tuesday's deadline for registration.

Instead, the 34-year-old Englishman flew from Italy to London where he was trying to obtain a U.S. visa at short notice, a European Tour official told Reuters at Congressional on Tuesday.

Rock had booked his place in this week's U.S. Open via an international qualifying event at Walton Heath, England last month.

Should he not make it to Congressional in time for Thursday's opening round, his spot would be offered to first alternate and fellow Briton Richie Ramsay, organizers said.

(Editing by Frank Pingue)