Ahmad Bradshaw sat quietly on his couch at home in Indianapolis last Sunday night watching the Giants play the Cowboys while his former Big Blue protégé David Wilson endured a running back’s worst nightmare on national television. While Bradshaw watched the game he held a football in his arms — a habit he follows even at home as a reminder to protect the ball in games — and with each Wilson fumble in Dallas he clutched that football closer to his chest as if there were linebackers about to burst into his living room trying to strip it from him. “I’ve been in that same predicament and it’s all mental’’ Bradshaw told The Post by phone on Thursday. “As a running back it gets into your head.’’ Bradshaw who lost six fumbles in the 2010 season and had to redefine the way he carried the ball if he was going to continue his career said he planned to reach out to Wilson before the Giants home opener against the Broncos on Sunday. After six seasons with the Giants Bradshaw was released in the offseason — a clear indication the team was ready to make Wilson the lead back. But in his leading-man debut Wilson fumbled the ball away to the Cowboys twice and was as big a reason for the Giants’ 36-31 loss as anyone. Coach Tom Coughlin indicated as much not sugar-coating the matter when he said “He cost us dearly.’’ So that has made Wilson’s week longer than that of anyone else on the team. Coughlin benched Wilson for the rest of the Dallas game after the second fumble and on Wednesday called Wilson a “marked man.’’ So this is the baggage Wilson will carry while awaiting his next carry at MetLife Stadium where there surely will be a hush of collective held-breath from the capacity crowd the first time he touches the ball.