The Minnesota Vikings list quarterback Tarvaris Jackson as doubtful for Sunday's game against the Kansas City Chiefs, but head coach Brad Childress isn't saying who will be the starting quarterback. Kelly Holcomb and Brooks Bollinger shared snaps in practice all week. Most people believe Holcomb will get the start. Childress let the quarterbacks know of his decision but neither quarterback was talking after practice. The coach said Friday that he doesn't want to take away the competitive advantage he feels he has by keeping the decision a secret. "I don't see the upside of putting it out there," Childress said after practice.