Mark Dantonio has played up the Michigan State-Michigan rivalry ever since he took the Spartans' head-coaching job.

But Dantonio also knows there's a line that shouldn't be crossed when discussing a rival, and in his mind, several of his players crossed it this past weekend.

In case you missed it, several Michigan State players took to Twitter to mock Michigan quarterback Denard Robinson and the Wolverines during Michigan's 41-14 loss to Alabama on Saturday night. Spartans starting linebacker Denicos Allen tweeted that Tommy Vento, a walk-on quarterback for Michigan State, is better than Robinson. Redshirt freshman safety Kyle Artinian was more direct, reportedly tweeting, "DENARD IS SOOOO BAD!" Freshman linebacker Jamal Lyles added, "I can play quarterback for the school in blue."

All the Robinson tweets were later deleted, but Dantonio wasn't too pleased about the Twitter display when asked about it earlier Tuesday. He called it "disrespectful" and said he would address the matter with his players. He even brought up Michigan State's blowout loss to Alabama in the 2011 Capital One Bowl.

"Our guys need to keep their mouths shut," Dantonio added. "That blunt enough? … Especially the ones not even playing."

Allen appeared to show some restraint early in the Michigan-Alabama game, tweeting, "I really wanna say somethin about this team I'm watchin... But I'm not." But then he soon added, "I coulda told all of y'all that this was gonna happen just to save y'all the pain."

For the most part, I enjoy following Big Ten players on Twitter as we get to see a bit of their personalities come through. Some players, like Purdue defensive end Ryan Russell, are particularly entertaining. But if I were a coach, I'd be very concerned about situations like the one that played out Saturday night.

Allen's last tweet about the situation came out Sunday afternoon: "Lol well apparently I hurt a lot of feelings sorry guys lol I guess we have to wait till October 20th to play some real football #GoGreen."

Michigan hosts Michigan State on Oct. 20. In case a four-game losing streak to the Spartans wasn't enough motivation for Robinson and his teammates, Michigan State players supplied them with some more.

"You need to approach this game with humility," Dantonio said. "When this becomes personal, that's when it crosses the line."