By just about any measure, the Open Championship is the most unpredictable of golf's four major championships.
The weather is wacky, the courses are unlike anything we see in the three stateside majors and there always seems to be unexpected challengers to the game's elite when the tournament is on the line.
Bottom line, it's difficult to predict the headlines that will emerge during the 2013 Open Championship at Muirfield.
That said, there are significant storylines heading into the season's third major that can't be ignored and will undoubtedly influence the headlines once the tournament begins.
How healthy is Tiger? How prepared is Phil Mickelson? Is there another first-time major winner coming? What about Ernie Els?
Welcome to a sampling of what everyone is talking about as the 2013 Open Championship prepares to tee off.