Tiger Woods withdrew from The Northern Trust on Friday morning, citing injury.

“Due to a mild oblique strain that led to pain and stiffness, I have to withdraw from the Northern Trust,” Woods said in a statement. “I went for treatment early Friday morning, but unfortunately I’m still unable to compete.”

Woods struggled Thursday during an opening-round 4-over-par 75 at Liberty National Golf Club in Jersey City, N.J.

“I just didn’t play well,” Woods said after his round. “Just one of those things where I just didn’t hit any good shots and didn’t make any putts.”

Woods, 43, entered the week ranked No. 5 in the world, but had played only 12 competitive rounds since winning the Masters in April. That included missed cuts at the PGA Championship and The Open Championship.

In his statement, he said he was “hopeful I can compete next week at the BMW Championship,” part of the season-ending FedEx Cup playoffs.