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 15 of the NFL season.

• 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 15 Risers

Dak Prescott (QB, DAL)

It's a bit amusing that after three weeks of futility, people were ready to write off Dak Prescott as a fluke and a product of Ezekiel Elliott. For starters, even if he is only an elite QB when Elliott is around, the fact remains that Elliott will be around, presumably, for the majority of the next five years. But more curious is that three poor games would supersede a year and a half of data that shows Prescott as a high level QB. Over the past two weeks, Prescott has got it together at just the right time as fantasy owners could really use him this week in Oakland. Prescott threw for a season high 332 yards and three touchdowns last week. Now admittedly a lot of that was yards after the catch by Dez Bryant and Rod Smith, but the Cowboys offense is back on track, eclipsing 30 points in back to back contests. Prescott is back in the circle of trust.

Marquise Goodwin (WR, SF)

I'll just say I read somewhere that Marquise Goodwin is "suddenly a reliable fantasy option" and an "upside WR3." I will also say anyone who thinks that hasn't been paying attention. Goodwin is a rock solid WR2. He's posted double digit fantasy points in four consecutive matchups. His last four yardage totals: 106, 99, 78, 83. He hasn't scored a touchdown since week 10, which, for a pure burner, would typically make him useless. Not Goodwin. He's had a high receptions and yardage floor. In his two full games with Jimmy Garoppolo, he's seen eight and 12 targets and is averaging 102 yards. Goodwin is a must start weekly option and one of the safest players at the position.

Theo Riddick (RB, DET)

It only took the Lions two years to figure out that Ameer Abdullah is a terrible football player. I am a big advanced metrics guy and Abdullah's athleticism is off the charts. But that can only take a guy so far. It's become readily apparent that Abulldah can't play. Finally, Jim Caldwell decided to just start Theo Riddick. Now Riddick is no athletic specimen and he's not a special player. He is a useful player and good at what he does. Riddick had ten carries and ten targets last week. He scored two touchdowns. The Lions won the game. While Riddick wasn't particularly effective, he was the best of the Lions RBs and it led to a victory. It looked good on the box score. That should be enough to keep him leading the charge in week 15, where he will once again be a usable fantasy option.

Hunter Henry (TE, LAC)

It seems that Father Time has finally gotten Antonio Gates. It took him a really long time, but he got there. Hunter Henry has now exceeded 15 fantasy points in three straight games. He's had no fewer than four receptions for 50 yards and scored in two of his last three. Henry has the skillset to be one of the best TEs in the league and the Chargers are finally letting him use it. Henry could be a difference maker at TE over these final two weeks.

Week 15 Fallers

Tom Brady (QB, NE)

I have watched football for a pretty long time. I have seen some really, really bad quarterbacks throw the ball. I know what horrendous QB play looks like. That is what Tom Brady displayed on Monday night. By no means do I think Brady is done or that this is anything more than a rut he will inevitably bounce back from. However, Brady is playing some of the worst football of his career at the worst possible time for fantasy owners. With the game being Monday night, the whole world got a front row seat to Brady's meltdown. He missed wide open throws to Cooks, Dwayne Allen, and Danny Amendola. He didn't see open receivers. He underthrew Cooks deep multiple times. It was a truly disastrous performance against a team he just threw four touchdowns against a couple weeks ago. Facing a Steelers defense that just gave up 38 points to Joe Flacco should be a get right spot, but Brady has already bungled back to back matchups. If he does it again, it will likely cost you a shot at a championship.

Robby Anderson (WR, NYJ)

Well, that was fun while it lasted. The Robby Anderson show has come to a premature halt in New York. Robby Anderson posted his first single digit fantasy effort since week 5 last week. I am not killing him for one bad game against the Broncos. He is here because of what happened to Josh McCown. Without McCown, Anderson will now receive his passes from Bryce Petty, which is only a step above receiving his passes from me. Anderson's high end WR2 value descends all the way to unstartable. That's how significant this drop is. Do not make the mistake of trusting Anderson with Petty, especially against Marshon Lattimore.

Tevin Coleman (RB, ATL)

I really don't get what Atlanta is doing. They had this hyper efficient offense in 2016 that featured Devonta Freeman and Tevin Coleman working in tandem. For most of 2017, they've ignored Coleman, who I believe is better than Freeman. In the two games since Freeman's return from his concussion, Coleman has eight and nine carries for 22 and 32 yards respectively. He hasn't scored a touchdown and he's been largely ignored in the passing game despite grading out as one of the best pass catching backs in the league. It doesn't make any sense, but there's enough data to know that it's reliable. Coleman is not worth starting when Freeman is active.

Stephen Anderson (TE, HOU)

There was a lot of buzz after week 13 when Stephen Anderson took over for C.J. Fiedorowicz and corralled five of 12 targets for 79 yards and a touchdown. One week later, he saw his target count cut his half and his receptions count by more than that. Anderson managed just 16 yards against the 49ers and now runs into the best defense in the league that just held Jimmy Graham catchless. The Anderson experiment has come to an abrupt end.

More Week 15 Lineup Prep