Padraig Harrington has slipped back down the field after a promising start to his opening round at the Northern Trust Open in California.

After two birdies in his first three holes, Harrington has now made the turn on 2-over par after also carding four bogeys on the fourth, seventh, eighth and ninth holes.

Harrington is currently trailing leader Cameron Tringale by seven strokes.

Darren Clarke, who is also in this week's field, will tee off later this evening.