By Mark Lamport-Stokes

MARANA, Arizona (Reuters) - A dumb-founded Keegan Bradley said even he was taken aback by his excessive spitting as he watched television replays of his play during the final round of last week's Northern Trust Open in Los Angeles.

However, once he saw for himself via the telecast how much he spat during his pre-shot routine, the PGA Championship winner issued a public apology on his Twitter account.

"To be honest with you, I really had no idea I was doing it," Bradley told reporters at Dove Mountain Tuesday while preparing for this week's WGC-Accenture Match Play Championship.

"And I feel bad.

"It might take some time but I will do my best to stop. It's something that I'm glad that's come up, because I'm able to kind of nip it now. It's just a thing where I'm watching myself."

"It's about visualization," the 25-year-old said. "It's kind of my way of staying not stagnant. It's something that you don't even really realize you're doing when you're in the heat of it.

"I will take a look at it and see if there are any improvements that I can make. But it's something that I've been doing and it's been working. Coming down the stretch, it (the time) does come up a little bit.

"But it doesn't seem to affect my ability, which is the most important," added Bradley, who earlier was presented with his trophy for winning the 2011 PGA Tour Rookie of the Year award.

Bradley has been drawn to play against Australian Geoff Ogilvy, tournament champion in 2006 and 2009, in Wednesday's opening round at Dove Mountain.

(Reporting by Mark Lamport-Stokes; Editing by Ian Ransom)