It’s still not known if Vikings quarterback Tarvaris Jackson will play in Thursday’s preseason finale in Dallas.  He suffered a sprained MCL in his right knee during the team’s second preseason game and did not play in the matchup against Pittsburgh last Saturday.  Jackson says his knee is still sore and he doesn’t have his full range of motion.  The Vikings are in Dallas Thursday for preseason action.  The regular season for the Vikes kicks off on Monday, September 8th in Green Bay.