Back injury forces McIlroy to withdraw at Bay Hill

Rory McIlroy has withdrawn from the Arnold Palmer Invitational in Orlando with a back injury.

The Northern Irishman's exit was announced by the PGA Tour before he started the tournament's third round.

The five-time major winner held a share of ninth place - nine shots back - after moving to four under on Friday with a round of 68.

Having birdied four of the first seven holes on the back nine, McIlroy had said he was "really pleased", adding he had played a "controlled, patient round of golf".

The 36-year-old, who was competing in his third PGA Tour event of the season, is due to defend his titles at the Players Championship at Sawgrass next week and the Masters at Augusta from 9-12 April.

A play-off win at the latter against Justin Rose last year saw McIlroy become the sixth man to complete a career Grand Slam, ending an 11-year drought at the sport's four biggest competitions.