When Philadelphia businessman Tom Knox released a statement yesterday saying he was seriously considering running for mayor in 2015 and thus not running for governor, political reporters didn't race to their phones.

It was worth a tweet, but not much more, because Knox has proved himself a fickle fellow.

He made a credible run for mayor in 2007, putting millions into the race and leading the field before eventually losing the Democratic primary to Michael Nutter.

But since then, he's just another dude who can't commit.

He announced his candidacy for governor in 2010, got consultants working for him, then abandoned the enterprise before even filing nominating petitions.

He publicly toyed with running for mayor again in 2011, conducting a poll and saying he could match Nutter dollar for dollar. He backed out again.

And in December, he was handing out "Knox for Governor" cards, telling people he'd be in the Democratic primary next year to challenge Gov. Corbett. Now, that's off.

So his latest change of course barely worth noting.

Knox has the money to make himself a top tier candidate if he commits. We'll know he has when he puts money into TV ads or files nominating petitions. Until then, it's no more than a tweet.