Simone Biles will not defend her Olympic gold medal on floor exercise.

USA Gymnastics says the six-time Olympic medalist has opted not to compete on floor.

She won gold in the event in Rio de Janeiro and placed second in qualifying last week. Jennifer Gadirova of Britain will replace Biles in Monday’s finals.

USA Gymnastics says Biles has not decided whether to participate in Tuesday’s balance beam final.

Biles is dealing with a mental block that in gymnastics is referred to as “the twisties.” She is having trouble figuring out where her body is in relation to the ground when in the air.