Head coaches Pete Carroll and Jim Schwartz can have a long conversation about Jim Harbaugh.

After the latest incident involving Harbaugh, where he allegedly used an expletive when giving Schwartz a hearty slap on the back after the 49ers tight 25-19 victory over the Lions on Sunday, it seems the former Chicago Bears quarterback has earned himself another rival.

When Harbaugh was the head coach at Stanford, he appeared to deliberately get under the skin of then-USC head coach Carroll. While Carroll was attempting to lead the Trojans to a BCS title, Harbaugh frequently made comments to incite Carroll, and was able to come away with two wins in three games.

Now, Harbaugh is embroiled in another dicey situation after his post-game handshake with Schwartz. Cameras caught an excited Harbaugh slapping Schwartz on the back in a way that appeared to be a shove.

I went to congratulate coach Harbaugh and got shoved out of the way, Schwartz said. And then I didn't expect an obscenity at that point, so it was a surprise to me at the end of the game. 

After the slap, Harbaugh appeared to jog to the locker room, but not before Schwartz became infuriated by the incident. Schwartz, 45, and Harbaugh, 47, are somewhat young compared to many NFL coaches, but there is a typical protocol to be gracious in victory, and Harbaugh didn't appear to be interested in that.

Harbaugh didn't slap Carroll on the back when Stanford handily defeated USC in November 2009 at the Los Angeles Memorial Coliseum, but the two coaches looked overtly annoyed with one another.

Cameras caught Harbaugh asking Carroll, what's your deal? after the game.

Here are videos from both incidents: