LAS VEGAS (AP) _ Don Helling of St. Charles, Mo., slipped into the second-round lead Tuesday afternoon in the Professional Bowlers Association Showboat Senior Invitational.

Helling battled his way to five PBA titles between 1967 and 1975 while competing on the regular tour. He also added a Senior title in 1995. His 3,748 pins for 16 games represent a 234.25 average.

If Mike Durbin maintains his second-place standing until the championship round on Saturday, he will have to find a substitute for the broadcast booth. Durbin handles play-by -play announcing duties for pro bowling on the ESPN2 telecast with fellow PBA Hall of Famer Marshall Holman. Durbin lies 57 pins behind Helling with a 3,691 total.

Three-time Senior champion Barry Gurney, seeking his first crown in two years, is third with 3,685 pins.

Rich Moores took over fourth place after knocking down 3,665 pins, and Chuck Lycan rounds out the top five, just one pin behind Moores. Lycan, 60, is the oldest bowler among the top 29.

The field of 349, all at least 50 years old, rolled eight more qualifying games Tuesday night before the first of three cuts.

Only the top 87 return Thursday morning for the fourth round. From there, the field is pared to 24 for match-play competition. The final cut comes Friday night when the top five scorers get seeded into the championship round of the tape-delayed broadcast.

The top prize is $20,000.