Description: According to Ben Goessling of espn.com, Vikings running back Adrian Peterson (foot) doesn\'t need surgery but is unlikely to play in Week 15.
Insight: The Vikings will know more when Peterson gets out of his walking boot and starts running. The running back said he plans on playing, but the team will have to see how his sprained foot feels when he runs.
Description: According to Vic Tafur of the San Francisco Chronicle, Oakland running back Rashad Jennings has passed his concussion tests.
Insight: Jennings proved to be a strong RB2 in place of the injured Darren McFadden from Weeks 9-13, but he suffered a concussion on Thanksgiving and missed Sunday\'s game against the Jets. Marcel Reece filled in and had 161 yards from scrimmage and a touchdown, but he\'ll return to fullback with Jennings back in the lineup. While Oakland\'s Week 15 matchup against the Chiefs has blowout potential, Jennings will be a RB2.
Description: Free agent righthander Roy Halladay will retire, according to CBS Sports\' Jon Heyman.
Insight: Always the perfectionist, Halladay struggled with shoulder problems and couldn\'t pitch at his usual high level. If the rumors are correct, he\'ll finish his career with a 203-105 record, 3.38 ERA, 1.178 WHIP and 2,117 stikeouts.