MLB

CHAMBERLAIN OK WITH RULES

TAMPA – Joba Chamberlain understood the Joba Rules last year, but that didn’t eliminate the fierce competitor from being frustrated when they were enforced.

“Last year it was kind of frustrating, having the rules [no back-to-back appearances; one day off for every inning thrown], but you understand what it was about,” Joba told reporters yesterday at the Yankees’ minor league complex.

The 22-year-old Chamberlain, who appeared in 19 games as Mariano Rivera’s setup man after making the transition from minor-league starter to major- league reliever, is going to open the year in the bullpen even though he will start camp this week throwing with the starters.

“We are going in at the beginning and understand there is an innings limit,” said Chamberlain, who was 2-0 with a 0.38 ERA last season when he fanned 34 big- league hitters in 24 innings thanks to a mid-90s fastball and filthy slider and allowed 12 hits. “I am excited to have a new challenge this year.”

george.king@nypost.com