Created: 09/25/2013 12:42 PM KSTP.com
By: Jennie Olson
Minnesota Vikings quarterback Christian Ponder is questionable for Sunday's NFL game in London against the Pittsburgh Steelers because of a rib injury.
Vikings coach Leslie Frazier says Wednesday's practice will "be a big signal in what direction we'll have to go."
Backup quarterback Matt Cassel is ready to step in if Ponder is ruled out.