Fox: I'd prefer grass. It saves our players' legs. But if need be, we'll go indoors or on their synthetic surface."

What's this? The Super Bowl coaches would prefer that their players practice on natural grass?  

...But Carroll echoed Fox's sentiments in saying he'd prefer to work his players on natural grass, if possible, and practice outdoors to prepare to play in the cold Sunday...

 http://espn.go.com/nfl/playoffs/2013/story/_/id/10357094/super-bowl-xlviii-snowy-practice-fields-concern-john-fox-pete-carroll