When “reformed” Louisville coach Bobby Petrino hired former Georgia defensive coordinator Todd Grantham, it seemed like a perfect marriage — if one were to assume a petroleum truck parking in a warehouse full of plutonium is a perfect marriage.

So maybe this won’t come as a surprise:

According to SI.com, Petrino has "feuded often" with Grantham since hiring him in January. The relationship between the two is so bad, one unidentified source told S.I., that Petrino would have fired Grantham by now if he had not given him a five-year contract worth nearly $1 million annually (which, by the way, wasn't real smart).

I’m not sure how much credence to give the report because I’m often leery of stories that rely on unnamed sources, particularly when the stories are reported in part by Thayer Evans, who has had a recent history of botched and/or overblown stories. Sports Illustrated’s Pete Thamel, who has a co-byline on the “Inside Read” college football notebook, has a bit more credibility.

But the nuggets reported by Evans and Thamel certainly are entertaining — and certainly plausible, given Petrino’s history.

It has been amusing to see so many national media members craft stories about the “new and improved Bobby Petrino,” whose long list of character flaws have been revealed at almost every career stop, most recently with the Falcons (where he walked out during his only season) and Arkansas (where he carried on an affair with an athletic department aide whom he had hired, leading to his firing, following a motorcycle crash involving the two).

Here’s the S.I. excerpt on Louisville:

Bobby Petrino says he’s changed. But in reporting a story about the new Louisville coach that is in SI’s college football preview, it appears Petrino is still just as difficult to work and play for. Sources with ties to the Cardinals’ football program and Petrino said there’s significant friction between Petrino and feisty defensive coordinator Todd Grantham. The two have feuded often since Grantham’s hiring in January.

So much that one source insists Petrino would have already gotten rid of Grantham if not for his guaranteed five-year contract that pays him nearly $1 million annually. He came to Louisville after four seasons as Georgia’s defensive coordinator. “He’s stuck with him,” a source said.

There’s also still lingering dissension among players about Petrino’s arrival. Some were so unhappy with Petrino’s frigid, explicit demeanor that they considered leaving early for the NFL’s supplemental draft in June according to one source.

“He’s a mean guy,” said Jamaine Brooks, a former Louisville defensive tackle who left this past spring. “He cusses you out. You’re never doing enough. He’s still Bobby Mother——- Petrino.”

Brooks initially supported Petrino’s hiring, which he quickly came to regret. “The way he came in doing business I didn’t like it,” Brooks said. “The way he treated people. He just wasn’t a good coach.”

So, the peace apparently didn’t last too long in Louisville.