NFL Week 9 Predictions: 4 Fantasy Performances That Will Kill Your Team

In the world of fantasy football, having a starter who's expected to perform well but ends up underachieving can be the single most devastating thing that kills your team.

So with that in minds, here are four matchups you need to be well aware of.

Chris Johnson: RB, Tennessee (vs. Bengals)

The Bengals have a Top 10 defense and the Titans rank dead last in rushing yards per game. Chris Johnson is proving to be the prime example of why RBs shouldn't holdout from training camp, and his 43 yards per game average is good enough evidence.

Sure, not having a passing game hurts, but if Johnson is as good as he thinks he is, then there's absolutely no excuse for his kind of underachievement.

So even if you start CJ this week, don't be surprised when he barely compiles 50 total yards against a stout Cincinnati defense, because they will shut him down.

Philip Rivers: QB, San Diego (vs. Packers)

If Philip Rivers is on your fantasy team, the only thing to be glad about is that San Diego no longer has to play the Chiefs this season. In both games against K.C., Rivers threw two picks and had zero TDs.

That said, he's not going to live up to previous standards this week at home versus the Packers, either (only seven TDs to 11 picks on the year, also). Green Bay has a solid pass rush despite a weak pass defense, and the Bolts offense isn't explosive enough to keep pace with Aaron Rodgers and the cheese. 

I'm not saying Rivers needs to be benched, but if your backup has a better matchup, it's not a bad idea to at least consider making the switch.

Rashard Mendenhall: RB, Pittsburgh (vs. Ravens)

When Baltimore visits Pittsburgh this week, Steelers RB Rashard Mendenhall won't be expected to have a big game. The Ravens have a Top Five defense and the Steelers are better in the passing game anyway.

Rashard's contributions this week will be mostly for additional pass protection against the Ravens pass rush, and on the ground he will only be used to keep Baltimore honest. In short yard situations he'll most likely be a decoy and most of his production will come on screen passes or check-downs.

So it's not that Balty will shut him down as it is that Mendenhall's opportunities will be limited to a more specific role.

Jay Cutler: QB, Chicago (at Eagles)

Everything in the Chicago offense revolves around RB Matt Forte. QB Jay Cutler is being limited by offensive coordinator Mike Martz and rightfully so, because Cutler has yet to really perform at a highly consistent level.

However, since he has such a strong arm, throwing the ball isn't the problem, but still being prone to INTs is. He may only have six thus far to nine TDs, but it's not like Jay's attempting 40-50 passes a game and going downfield on half of them like Drew Brees.

And this week the Bears play at Philadelphia whose pass defense ranks No. 10 to Chicago's No. 17 pass offense. Include Philly's offense becoming more confident and the Bears may have to play catch up in Week 9. Advantage, Philadelphia.

Be sure to check out John on Bleacher Report. 

You can follow him on Twitter @ Sportswriter27.