Vikings quarterback Sam Bradford back at practice

Minnesota Vikings quarterback Sam Bradford warms up for the team's NFL preseason football game against the Seattle Seahawks, Friday, Aug. 18, 2017, in Seattle. (AP Photo/Scott Eklund)

EDEN PRAIRIE, Minn. — Minnesota Vikings quarterback Sam Bradford has rejoined the team for practice for the first time in two weeks, raising the possibility of him coming back as the starter for the upcoming game at Chicago.

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Bradford went through drop-back throwing drills on Thursday during the initial portion of the workout that was open to reporters. He has been kept out of the past three games because of a sore left knee that stemmed from the season opener.

Coach Mike Zimmer said he doesn’t know yet whether Bradford or backup Case Keenum will start on Monday against the Bears, but the extra day before the game will give Bradford a better chance to be cleared for a return.

The Vikings (2-2) have lost two of their three games with Keenum.