Kansas City Chiefs v Minnesota Vikings
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Vikings star Justin Jefferson left last Sunday's loss against the Chiefs in the fourth quarter with a hamstring injury and did not return. After much uncertainty surrounding the severity of the injury and how long he would be out, the Vikings answered the question by placing the star wide receiver on injured reserve.

On Saturday, ESPN reported that doctors believe Jefferson could be sidelined four to six weeks. Jefferson will undergo further imaging tests in a month to determine when he's able to return.

Jefferson slipped on the U.S. Bank Stadium turf while running a route against Chiefs cornerback Trent McDuffie late in Kansas City's Week 5 27-20 victory. He was ruled questionable to return and did remain on the sidelines after limping off for medical attention. But he didn't take another snap before the final buzzer, leaving rookie Jordan Addison to serve as Kirk Cousins' top pass target.

Head coach Kevin O'Connell made a personal visit to Jefferson's locker on his way to the podium after the game, attempting to console the wideout, who did not speak with reporters. On Monday, O'Connell told reporters that Jefferson would solicit multiple medical opinions on his hamstring.

"We've got to get the MRI of it and take a look and find out exactly what it is, where it is, if there's any other factors that go into it and determine what the best decision (is) for him to get him back to 100 percent as fast as possible," O'Connell said. "He's down today. He obviously is one of the most ultra-competitors I've ever met, and shoot, he was trying to go back in the game as it was yesterday. So we're gonna have to medically make a good decision and help kind of almost protect him from himself a little bit."

Justin Jefferson
MIN • WR • #18
TAR53
REC36
REC YDs571
REC TD3
FL1
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Fantasy focus

From CBS Sports Fantasy Senior Editor Dan Schneier: With Jefferson out, most Fantasy Football managers will turn their attention to rookie first-round draft pick Jordan Addison as the next man up. While it's possible this is the opportunity Addison needs, he's more likely to be currently rostered than K.J. Osborn, who is actually more likelier to have an edge over the rookie when it comes to future route participation, snap share and built-in rapport with quarterback Kirk Cousins.

As mentioned by host Adam Aizer on the Fantasy Football Today podcast earlier this week, Osborn has scored at least 14.6 PPR points in eight of 11 games with at least seven targets, averaging 16.1 points per game in those 11 games. However, in 48 total games with the Vikings, Osborn has only averaged 5.5 targets per game – including the four games that former Vikings WR Adam Thielen was out for. Osborn's target share should take a jump without Jefferson on the field given the fact that Jefferson has averaged 11.75 targets per game in his four full games this year, but he's more of a WR3 while Jefferson is out. 

Entering Week 5, Osborn was dead last (69th out of 69 wide receivers) at 0.69 yards per route run minus busted coverages. As for Addison, the rookie's role is likely to grow from a snap share standpoint, and assuming he can do more with his routes than Osborn, his rapport with Cousins could build fast. Addison's upside lands him in the borderline WR2/3 range. Finally, T.J. Hockenson is set to take a jump in targets as well. Hockenson has averaged six targets per game this season – that number could jump as much as 25-50% per game. He's already an every-week starter at TE, but during Jefferson's absence, Hockenson has the opportunity to become more of a weekly difference maker at the position.

Need help replacing Jefferson in your Fantasy lineup? Check out the early waiver wire for Week 6 for possible options.