According to Rollingstone.com, THE ROLLING STONES will not tour to mark their 50th anniversary this year.

Rolling Stone has learned after separate interviews with Mick Jagger and Keith Richards.

"Basically, we're just not ready," says Richards. Instead, 2013 is the new goal. "I have a feeling that's more realistic," he adds.

But Stones insiders say that one reason for the delay is Richards' health, which has raised questions about his ability to make it through a worldwide tour.

The quality of the guitarist's performances declined after he suffered a head injury on vacation in Fiji in April 2006, midway through the Bigger Bang tour.

Many fans observed that his playing in Martin Scorsese's Shine a Light documentary later that year was weak – and often inaudible.

After the tour, Richards put the guitar down completely. "You are looking at a very rusty Keith Richards right now," he told Jimmy Fallon in 2010.

"If you've been on the road for two years and suddenly you stop, you put it down for a little bit. And then a little bit longer and you say, 'I really got to catch up, man.'"

A top concert-business source confirms the reservations over Richards' condition. "They don't want to do a full tour," he says.

"They don't want to travel, and there are concerns about Keith's health."

A more likely scenario would see the band camping out for multi­night runs in arenas, similar to Prince's recent stands in New York and Los Angeles.