AVONDALE, LA. -- A back injury forced defending champion Seung-Yul Noh of Korea to withdraw midway through his second round Friday at the Zurich Classic of New Orleans at TPC Louisiana.

Noh, 23, withdrew after playing holes 10 through 17 at even par and finished his 26 holes at 1-over par after shooting a 73 Thursday on the 7,425-yard, par 72 Pete Dye layout.

Noh earned his first PGA TOUR win in New Orleans last year, becoming the seventh first-time winner in the past 10 years in the Big Easy.