The source of this comes from some undisclosed tabloid, but Jeannette Walls’ of MSNBC writes at the end of her “Scoop” column:

Paris Hilton’s new sweetie has been warned to do something that might be difficult: stay out of the spotlight. New Arizona Cardinal quarterback and former USC star Matt Leinart was warned by his team that if he’s serious about football, he shouldn’t be photographed out late at night dancing and drinking with his partying heiress girlfriend, according to the Star. “Matt took it very seriously,” a source told the tab, “almost to the point of tears.”

Leinart never had a problem at USC, so don’t worry Arizona fans, or Buzzsaw fans (Deadspin’s affectionate nickname for the Cards), the man will be ready on gameday.

Buzzsaw Asks Leinart To Tone It Down A Tad [Deadspin]