Verplank, who bogeyed the 18th hole for the second consecutive day, turned in a 69 to match Marino at 19-under 197. They are two strokes ahead of Davis Love III (64) and Scott Sterling (66).
This is the final PGA Tour event of the season. Players are fighting to get into the top 125 on the money list to keep their PGA Tour cards for next season.
Three of the top-four players on the leaderboard are safe for next year. Sterling is 153rd on the money list and needs a good round Sunday if he is to remain on tour in 2009.