Answer:

OLDPRO

Answer	Crossword Clue
OLDPRO	Senior's Tour competitor
OLDPRO	Seasoned veteran
OLDPRO	One who knows the ropes

OLDPRO	Veteran
OLDPRO	Rookie's teacher
OLDPRO	Rookie's mentor
OLDPRO	Seasoned vet
OLDPRO	One with plenty of experience
OLDPRO	Grizzled veteran
OLDPRO	No newbie
OLDPRO	Vet

OLDPRO	Skilled hand
OLDPRO	Seasoned player
OLDPRO	Tyro's opposite
OLDPRO	Past master
OLDPRO	Seasoned hand
OLDPRO	Master
OLDPRO	Expert
OLDPRO	Nicklaus is one

OLDPRO	No neophyte