DEARBORN, Mich. -- Jack Nicklaus has withdrawn from this week's Senior Players Championship because of muscle spasms.

''It's always frustrating when you can't play,'' Nicklaus said Wednesday after pain forced him to stop an afternoon practice session after hitting about 15 balls.

Nicklaus said he enjoyed nine holes of golf on Tuesday in Ohio with family and friends. However, he was in pain Wednesday morning and it lingered until he withdrew from the pro-am after nine holes later in the day.

''I just don't like to be in the position of keeping somebody out of the tournament,'' Nicklaus said. ''Would I like to play? You're darn right I'd like to play. I thought after playing yesterday, 'Boy, I am ready to play. I am ready to go.' I woke up this morning and I couldn't stand on my right side to save my life.

''I'm 62 years old. I'd rather do what I did yesterday than be worried about what I was trying to do out here.''

The $2.5 million Senior Players Championship starts Thursday at the TPC of Michigan.

Nicklaus, who has played just three competitive tournaments this year, did not play in the U.S. Senior Open last month because of a recurring back problem, which also forced him to withdraw from the Senior PGA Championship earlier in June. The Associated Press