Despite some signs early in the week that he might be able to play through the injury yet again, it appears as if Dalvin Cook's shoulder will sideline him for at least Week 16. ESPN reported Thursday that Cook is not expected to play in Week 16, with an additional report noting Cook could be held out for Week 17 as well, with the Vikings hoping to save him for a potential playoff run.

That is obviously huge news for Fantasy players, because Cook has been one of the best running backs in football — No. 3 in non-PPR scoring and No. 2 in PPR. And that's even after leaving two of his last three games early in the second half as a result of the injury. That leaves a massive hole in Fantasy lineups, and we're not quite sure how to go about filling them just yet.

Alexander Mattison, a third-round pick rookie, has been Cook's primary backup rushing for 462 yards on 100 carries and showing some acumen in the passing game as well. However, he missed Week 15 due to an ankle injury, so his status for Week 16 isn't currently known.

Mike Boone is next in line, and he rushed for two touchdowns in the second half of last week's game with Mattison and Cook out. He is an undrafted free agent out of Cincinnati who tested well at the combine but never had more than 110 carries in a season in college. However, the Vikings showed in Week 15 they trust him to lead the way if needed, as backup Ameer Abdullah had just five carries to Boone's 13.

When we get to Monday night, the decision Fantasy players will have to make is simple: If Mattison plays against the Packers, you'll start him as a viable No. 2 Fantasy RB. If Mattison doesn't play, you'll start Boone, again as a viable No. 2 Fantasy RB. Boone isn't the same caliber of prospect Mattison is, just as Mattison isn't the same caliber of player Cook is, but this is a Vikings team that is intent on running the ball, so whoever ends up the primary back will be someone you want to have in your lineup for the Fantasy championship.

The problem is, we may not know until Monday night. If you can add both Boone and Mattison, do so now. Boone is still available in 65% of CBS Fantasy leagues, while Mattison is still out there in 36% of leagues. Whether you have Cook or not, adding both of these players should be the number one priority for all Fantasy managers — either to start whichever ends up playing, or to prevent your opponent from starting one. 

Where things get tricky is if you can only add one, because we may not know who is starting until Monday night. We'll see how Mattison gets through this week of practice, but if we get to Sunday afternoon and there is no clear indicator of whether he will play, you will have to either avoid this backfield entirely, or make sure you have another option for Monday night's game in the flex. That's a risky proposition, given how concentrated these offenses are — there isn't really anyone on Green Bay or Minnesota who is widely available who you would be comfortable starting. In that case, you might be better off avoiding Minnesota's backfield entirely; but that's only if you can only add one of Boone or Mattison and we don't know their status by Sunday. You should still try to add either or both wherever you can. 

Every year, injuries play a significant part in determining who wins Fantasy championships, and this Vikings situation figures to go a long way in determining who will take him countless trophies in 2019. Make sure you're prepared for every possibility.