The Vikings have called teams to gauge what they could get in return for Tarvaris Jackson, according to a league source. Minnesota currently has four quarterbacks on their roster, which needs to be trimmed to 53 players by Saturday. Coach Brad Childress has said that the team could keep all four, but it appears unlikely. Jackson has been mentioned in trade rumors ever since the Vikings signed Brett Favre last month. "You never know with this business, period," Jackson told the Star Tribune. "I just take it as it is. Whatever happens, happens. I can't control it. I just try and get better, that's it. I can't worry about [whether he gets traded or released]. I'm not worried about it because I can't control it. Whatever is going to happen is going to happen whether I worry or not."