Skelton had been in a battle for the No. 1 job with Kevin Kolb, who came to the Cardinals prior to last season and started the first seven games in 2011.
Kolb then missed six weeks with a toe injury, and when he returned late in the season he suffered concussion-like symptoms after taking a blow to the head against San Francisco.
Skelton made seven starts last year, completing 54 percent of his passes for 11 touchdowns.
"We feel like the quarterback that gives us the best chance to win is John Skelton," Coach Ken Whisenhunt said Friday.
Skelton threw for 131 yards and a touchdown during the exhibition campaign. Kolb had 203 passing yards with a single touchdown.
Skelton is in his third year with the Cardinals, having played his college football at Fordham.