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 risers and fallers heading into Week 2 of the NFL season. Dynasty owners, check out our separate Dynasty Risers/Fallers segment as well.

• Quarterback fantasy football rankings
• Running back fantasy football rankings
• Wide receiver fantasy football rankings
• Tight end fantasy football rankings
• Kicker fantasy football rankings
• FLEX fantasy football rankings
• Defense (D/ST) fantasy football rankings
• Superflex fantasy football rankings
• IDP fantasy football rankings
• Dynasty fantasy football rankings

Week 1 Risers

Kareem Hunt (RB - KC)

It doesn't get more obvious than this one. While Kareem Hunt saw a similar snap share as Spencer Ware did last year (around 60%), he dominated touches over Charcandrick West (West only had two carries and a reception). Hunt had the greatest debut for a rookie RB in NFL history, despite starting it off with fumbling on his first career touch. It goes without saying that the arrow is pointing upward on Hunt.

Mike Gillislee (RB - NE)

I was admittedly skeptical that Mike Gillislee would take over a role that did not exist before LeGarrette Blount. It appears I was very, very wrong. Gillislee will still be entirely touchdown dependent for production, but double digit touchdowns seems like a virtual certainty. As long as you can deal with the weeks where he gets you 50 empty rushing yards, you will enjoy the weeks he falls into the end zone twice.

Javorius Allen (RB - BAL)

While the fact that he got more touches than Terrance West has more to do with game script, more importantly is the Danny Woodhead hamstring injury. With Woodhead out, West can't literally handle every snap and the Ravens have shown that Buck Allen is the next man in line for touches. He is probably worth a waiver add.

Tarik Cohen (RB - CHI)

Jordan Howard played 57% of the offensive snaps. Tarik Cohen played 42%. That number could reach 50-50 if Howard keeps dropping game winning touchdown passes on passing downs. Cohen is a far superior pass catcher and looked like the all around better player in week one. The Bears should have won the game and it would have been because of Cohen. Without any real wide receivers remaining, Cohen and Howard may share the field a lot with Cohen operating out of the slot. He has standalone flex value already with the upside for more.

Ty Montgomery (RB - GB)

There was admittedly some preseason concern over what Ty Montgomery's workload would actually look like. Well, he played 92% of the snaps and it would've been even higher if he didn't miss a handful of plays with a leg/ankle injury that turned out to be nothing. Montgomery has RB1 upside if he can get the touchdowns. He got one on Sunday. He just needs to stay healthy.

Adam Thielen (WR - MIN)

Man did he look good. He has some of the best hands in the league right now and looks like a lock to shatter his ADP. Nine catches for 157 yards was one of the best WR performances in a dismal week one. Thielen looks like a WR2 and an every week starter in fantasy.

Week 1 Fallers

Eddie Lacy (RB - SEA)

Not that this is a surprise, but you never should've drafted Eddie Lacy. He is truly terrible at football. I suspect he will be out of the league within the next two years. Three yards on five carries. I don't care how bad your offensive line is, that's just unacceptable. Lacy should be cut everywhere.

Rob Kelley (RB - WAS)

Here is another guy that has no business being in the NFL. Kelley posted 30 yards on 10 carries. He didn't catch a pass. He is going to cede that job to Samaje Perine eventually because an NFL team just cannot continue with Rob Kelley as their starting RB.

Paul Perkins (RB - NYG)

We start with a trio of RBs that are so bad they should not be in the NFL. Paul Perkins managed a paltry 16 yards on seven carries. He was outplayed by Shane Vereen and Orleans Darkwa. A changing of the guard is imminent. The Giants offensive line can't block, but Perkins can't play football. Darkwa will be the early down guy and Vereen the passing down guy within a few weeks.

Brandon Marshall (WR - NYG)

I told you all that Brandon Marshall was done. He looked done to me. He can no longer generate separation against decent coverage. He was never all that fast, but now he really lacks burst. He looks like a man that is 33 years old. Perhaps Odell Beckham's return will help open things up for Marshall, but I just don't think Marshall can play much anymore.

More Week 2 Lineup Prep