Whether due to their own play, the play of others, or injuries, players' stock increases and decreases on a weekly basis. Perhaps more than any other, the NFL is a league that experiences ups and downs at a rapid pace. With only 16 games, there’s little room for error and seemingly endless opportunities for improvement. The same goes for fantasy football, and managing rosters effectively is key to winning that championship.

Throughout the season, players get hot and see an increased role while others struggle and fight to stay relevant. Experienced fantasy players know this happens every year. In this weekly column, we’ll showcase those who have taken important steps forward and those who have taken steps back.

These are the key fantasy risers and fallers heading into Week 16 of the NFL season.

Week 16 Risers

Blake Bortles (QB, JAX)

I will preface this by stating that I still believe Blake Bortles is terrible and will ultimately be the reason the Jaguars do not make the Super Bowl. For fantasy purposes, he's been a star recently. Over the past four weeks, Bortles is averaging over 20 fantasy points per game and has thrown multiple touchdowns in three straight contests. In week 16, he gets the 49ers that just allowed two touchdown passes to Marcus Mariota, who isn't even averaging a touchdown per game. Bortles is without his top three WRs and doesn't seem to care. He will make it work with Keelan Cole and Jaydon Mickens.

Robert Woods (WR, LAR)

After missing a few weeks with a shoulder injury and watching Cooper Kupp ascend, there was some concern over Robert Woods' role/volume upon his return. Those concerns have been assuaged. Woods caught six of seven targets for 45 yards and a touchdown. While those numbers aren't great, he was clearly ahead of Kupp and Jared Goff didn't have to throw much last week as the Rams obliterated the laughably bad Seahawks to the point where the halftime score was 34-0. The Titans should at least make the Rams have to throw a little more this week. Woods is right back to being a WR2.

Dion Lewis (RB, NE)

Sure, I could've gone with Todd Gurley or Kareem Hunt, but Dion Lewis is the one who saw the biggest jump in fantasy value. Lewis had previously been a volume based flex play with no touchdown upside. With the injury to Rex Burkhead, Lewis is going to see an increase in snaps as well as likely take over the goal line role. Lewis' floor remains relatively high while his ceiling increases significantly as the prospect of scoring a touchdown becomes that much more likely. We know Tom Brady isn't throwing touchdowns (has just two in the last three games) so Lewis could be a league winner in week 16.

Greg Olsen (TE, CAR)

I guess his foot is fine? Greg Olsen caught nine of 12 targets for 116 yards and a touchdown last week. He's certainly not 100% healthy, but he's clearly healthy enough to be an elite TE1 again. With Devin Funchess being ineffective, Olsen flat out dominated. He needed a prove it week before fantasy owners could trust him and this was just it. Olsen can be started in fantasy title games.

Week 16 Fallers

Tom Brady (QB, NE)

How is it not Tom Brady? It is week 16 and the GOAT has created a legitimate question as to whether you should start him this week. If you roster Blake Bortles, Case Keenum, Nick Foles, and Tom Brady, is Brady legitimately fourth on this list in startability? I really think he is. Over the past three weeks, Brady has thrown for fewer touchdowns (2) than T.J. Yates (3) and Yates only played in two games in that span! I think it's fair to say weeks 13, 14, and 15 are the three most important weeks in the fantasy season. Week 15 is undoubtedly the single most important week. In those three weeks, Brady's finishes are QB27, QB23, and QB18. Earlier in the season I said Brady was done being a truly elite option, but is still one of the best in the league. Now that we are in the final stages of 2017, Brady might just be done. If you roster him, I have no idea how you can justify starting him beyond "he's Tom Brady."

Jordy Nelson (WR, GB)

I know. I know. How can Jordy Nelson's value actually fall when it's been unanimously agreed he should not be rostered in fantasy leagues for almost two months now? Well, the return of Aaron Rodgers brought back some hope that Nelson's value would come along with him. Rodgers' return proved to just be more of the same for the Packers offense. Number one receiver Davante Adams continues to be relatively QB proof while Nelson continues to be a guy best left on the waiver wire. Since week 7, Nelson's highest yardage total is 35. Yes, you read that correctly. Jordy Nelson has not surpassed 35 yards since week 6. He has not scored a touchdown since week 5. He has not eclipsed 7.5 fantasy points since week 6. There is no justification for him being on any normal sized fantasy roster in any format.

Rod Smith and Alfred Morris (RBs, DAL)

This one is obvious, but it bears mentioning. Rod Smith and Alfred Morris both had flex value over the past three weeks. Morris was handling the early down work while Smith would mix in on passing downs and dominate goal line touches. Ezekiel Elliott is back this week, which means Morris and Smith will barely see the field. They go from viable starting options to yes you should absolutely drop them.

Hunter Henry (TE, LAC)

The Chargers' TE situation has been near impossible to figure out this season. Hunter Henry had been coming on strong and looked poised to close out the season hot. Instead, he lacerated his kidney last week. Somehow, this Chargers team has seen two of its starters lacerate a kidney over the past three years. I don't even know how that happens, but it happened to Keenan Allen in 2015 and now it's happened to Henry. Antonio Gates doesn't have much left, but Henry will certainly not be playing over these final two weeks. The injury cost Allen the entire second half of his season. I don't expect to see Henry again.

More Week 16 Lineup Prep