There's nothing more maddening for fantasy football owners than a wildly inconsistent player who puts up huge totals one week but disappears the next. This is even more true in Week 15 with the fantasy playoffs in full swing.
Starting a player on his down week can carry the awful side effect of dooming your championship aspirations. Only the best teams have survived to this point, and you need your top guns playing at their best to advance to the next round.
Sitting a player who puts up massive totals is just as devastating, though, for the same reason.
With that in mind, here's a look at a few boom-or-bust stars—a start 'em, sit 'em guide to aid your decision-making as you put together your lineup for Week 15.
Start: Matt Ryan, QB, Atlanta Falcons
You have to look all the way back to Week 7 to find the last time Matt Ryan put up over 15 fantasy points in a game.
The 2013 season has been rough for the Atlanta Falcons, thanks to a rash of injuries that includes a few of Ryan's top offensive weapons (Julio Jones, Roddy White and Steven Jackson). White and Jackson are finally healthy, however, and the offense is starting to click.
Before a dismal outing in the snow at Lambeau Field in Week 14, Ryan had passed for 603 yards in his previous two starts.
Atlanta hosts Washington in Week 15, and this is a perfect opportunity for Ryan and his offense to explode. Washington gave up 45 points to the Kansas City Chiefs in the snow, and rumors are flying about Mike Shanahan's impending departure as head coach, as Bleacher Report's Mike Freeman detailed.
Mark Maske of the Washington Post wrote a column after the loss to Kansas City saying the relationship between owner Daniel Snyder and Shanahan could be "too damaged to repair," and it seems inevitable that he'll be fired.
Needless to say, Washington is a complete mess right now, and its defense especially so. Ryan will have a field day at home, putting up huge fantasy totals for owners smart enough to start him.
Projected Stats: 330 total yards, three touchdowns.
Sit: Eli Manning, QB, New York Giants
As noted by the NFL on ESPN, he threw his 20th interception of the season in Week 14 against the San Diego Chargers, tying rookie Geno Smith for the league's worst mark:
Eli Manning now with 20 interceptions, tying Geno Smith for the NFL lead. #NewYorkNewYork— NFL on ESPN (@ESPNNFL) December 9, 2013
Five times this season, Manning has scored nine fantasy points or fewer, compared to just one game in which he eclipsed 20 points. He still has the same potential for greatness as ever, but it's been absent for most of this season.
Coming into town this weekend to take on the Giants are the Seattle Seahawks, which is even worse news for Manning and the Giants.
Seattle comes into the game with the No. 2-ranked fantasy defense against quarterbacks, and the Seahawks will be playing with a chip on their shoulder after getting beaten by the San Francisco 49ers in Week 14.
Projected Stats: 180 total yards, one touchdown, two interceptions.
Start: DeSean Jackson, WR, Philadelphia Eagles
It's hard to find a bigger boom/bust player than DeSean Jackson.
The enigmatic Philadelphia Eagles receiver has totaled 15-plus points five times in 2013, and he's scored eight points or fewer on six occasions. Making matters worse, his poor performances haven't necessarily matched up with poor matchups—he simply disappears sometimes.
Not surprisingly, Jackson looked extremely uncomfortable playing in the heavy snow in Week 14, but he did manage to catch a touchdown pass and score 11 fantasy points in those blustery conditions.
He'll keep that positive momentum going in Week 15 when the Eagles head up North to take on the Minnesota Vikings—a team not known for its ability to shut down receivers. The Vikings feature the league's No. 27-ranked fantasy defense against wide receivers, allowing 25 points per game.
Chicago's receivers totaled 41 points in Week 13, and Minnesota has allowed at least 22 points nine times this year.
Jackson's speed and quickness are best seen when he plays indoors. He'll have a field day getting open at the Mall of America Field, and Nick Foles has been hitting open receivers this year.
Projected Stats: Seven catches for 140 yards and two touchdowns.
Sit: Chris Johnson, RB, Tennessee Titans
Don't even think about starting Chris Johnson in Week 15 when the Tennessee Titans host the Arizona Cardinals.
Johnson comes into the game as the league's No. 8-ranked running back, averaging 11.5 points per game, which is a respectable number. But he's been wildly inconsistent this season, totaling nine points or fewer on eight occasions while going over 15 points four times.
As a result of his disappearing act and bloated salary, the Titans are expected to release Johnson after the season, as noted by NFL Media PR, via Mike Silver of NFL.com:
Also from @MikeSilver: Titans RB Chris Johnson "almost certainly gone after this season with his big salary and lack of production.”— NFL Media PR (@InsideNFLMedia) December 8, 2013
Things aren't going well for the Titans right now.
Meanwhile, Arizona comes into town in Week 15 with a Wild Card spot in its sights and with the NFL's top-ranked fantasy defense against running backs. The Cardinals have allowed just 9.9 points per game, and just 6.6 points per game in their last five.
This won't end well for Johnson, the Titans or you if you start him on your fantasy football team.
Projected Stats: 45 total yards, zero touchdowns
Note: Fantasy stats and information courtesy of ESPN.com.
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