Keenum has led the Vikings to five straight wins since taking over for Sam Bradford, who was placed on injured reserve last week with a left knee injury, with the team activating Teddy Bridgewater in a corresponding move.
Before being benched in favor of Jared Goff last season, Keenum went 4-5 with nine touchdowns, 11 interceptions, and a QB rating of 76.4 for the Rams.
The Vikings are in first place in the NFC North at 7-2 and face the NFC West-leading Rams, also 7-2.
FOX Sports' Jay Glazer reports the Vikings were "very tempted" to start Teddy Bridgewater this week against the Rams.
Zimmer said the decision to start Keenum, who spent the 2015 and 2016 seasons with the Rams, was "not difficult" as his team prepares for Sunday's important home game at U.S. Bank Stadium. Case Keenum with the 7-2 Minnesota Vikings going up against the 7-2 Rams.' I'm excited.More news: United Kingdom minister offers parliament new vote on any Brexit deal
In the meantime, under Keenum, the Vikings' pass attack ranks 12th-averaging 245.8 yards per game.
Zimmer said Bridgewater is ready now to play in a game. This game likely comes down to which offensive line holds up more, as these defenses are both one of the best at sacking the quarterback and creating game changing plays. The Vikings play December 10 at the Panthers. He did start nine games for Los Angeles past year, completing 60.9 percent of his passes with nine touchdowns and 11 interceptions. Overall, the Rams have been the more consistent team, and I trust Goff and this offense to have more success than I do Keenum and banged up weapons.
"If it ain't broke, don't fix it", Griffen said.
If you say it's you, I call liar.