Golf-PGA-Injured Katayama and Cejka pull out of Oakland Hills

(Updates with Cejka withdrawal)

BLOOMFIELD HILLS, Michigan, Aug 6 (Reuters) - Japan's Shingo Katayama and German Alex Cejka withdrew from the U.S. PGA Championship on Wednesday because of injuries.

Katayama, ranked 52nd in the world, pulled out due to a recurring back problem while Cejka cited an arm injury.

Americans Michael Allen and Tom Pernice junior have replaced Katayama and Cejka in the field at Oakland Hills Country Club.

Ninety-three of the world's top 100 players will be competing when the 90th PGA Championship starts on Thursday. (Reporting by Mark Lamport-Stokes; Editing by Clare Fallon)