By Simon Evans PALM BEACH GARDENS, Florida (Reuters) - Golf great Jack Nicklaus said on Sunday Rory McIlroy was wrong to walk off the course at the Honda Classic but said the world number one would be back to his best in time for the Masters next month.

McIlroy withdrew after eight holes of his second round on Friday, initially saying he was in a "bad place mentally" and then later citing toothache.

"He shouldn't have walked off the golf course. I think that was unfortunate, because if he had thought about it for five minutes, he wouldn't have done it," Nicklaus, who won a record 18 major titles, told the Golf Channel.

McIlroy has played just four full professional rounds in three months, missing the cut in the Abu Dhabi Championship in January and suffering a surprise first-round exit in the WGC-Accenture World Match Play Championship last week in Arizona.

Nicklaus said he suspected McIlroy's rash decision was caused by the impact of that slow start.

"He's a good kid, he's a sharp kid and I just think he is so frustrated with what is happening and the way he has played for last month or so that it just got to him.

"That would be my assessment. I may be speaking out of school. I really don't know, I haven't talked to him," he added.

Nicklaus was dismissive of the idea that McIlroy's change of clubs from Titleist to Nike might be behind his poor form.

The American said he played with different equipment in the United States, England and Australia and that McIlroy would cope with the adjustment.

"I went back and forth with all those different balls and clubs and frankly you have just got to learn to deal with it. Not everything is perfect. His talent is so much greater and so much bigger influence on his golf game than his clubs, he could play with anything," Nicklaus said.

The American said he frequently talked to McIlroy and had a chat with him just before the start of this week's tournament.

"I talked to him on Monday. We talked, I said ‘don't worry about your golf clubs, that will come around, you are too good a talent, just go and play golf'.

"I am sure that Nike will work with him to make sure he will get what he needs to get. He will be fine. When the Masters rolls around Rory McIlroy is going to be playing just fine.

"I know that Rory is such a good player, a talented player, a good kid and he wants to do right."