The Oakland Athletics exercised their $4 million contract option for outfielder Jay Payton on Monday that keeps him with the club through next season. Also, the A's declined to exercise their option on right-handed pitcher Keiichi Yabu, who signed a $1 million, one-year contract last January but was disappointing in his first major league season. The 32-year-old Payton would have received a $500,000 buyout if the team hadn't decided to keep him. ``He was a huge boost for our offense,'' A's assistant general manager David Forst said. ``When he came over here, we said at the time of the trade that having that option was attractive because we knew we'd be able to keep him beyond this year. Jay's a professional. He fit in great with the clubhouse. He's another great veteran our young guys can learn from.'' Payton had expressed his desire to return to the A's next year after being acquired in a July trade with the Red Sox that sent right-handed reliever Chad Bradford to Boston, where Payton was unhappy as a backup behind Manny Ramirez, Johnny Damon and Trot Nixon.