In a lot of ways, red zone performance is the crux of fantasy football.

We don't want a running back who gets spelled when the offense crosses the 20. We don't really like if our receiver doesn't get targeted near the goal line. And it makes sense. A touchdown is such a big swing in fantasy football that we have to check out red zone performance if we really want to understand who to trust and who not to trust.

So, here are 10 players whose 2014 red zone performance isn't likely to be repeated in 2015: for better and for worse.

5 Overperformers in 2014

Demaryius Thomas, WR, Denver Broncos
This one is a bit obvious, but red zone stats, Derek Carr threw for 18 touchdowns on 44 pass attempts last year. That conversion rate, 40.6%, was tops among all quarterbacks with, well, more than one passing attempt. I'm not buying it, and I don't think you should either. Despite his touchdowns, Carr owned a Passing NEP of -40.94, second-worst in the NFL. Only 41.0% of his drop backs led to positive NEP gains last year. The red zone production doesn't match up with the rest of his work, and that should allow us to be skeptical.

5 Underperformers in 2014

A.J. Green, WR, Cincinnati Bengals
I'm not really sold on a full-on resurgence from A.J. Green this year, but I'd be doing myself and you, more importantly, a disservice if I didn't mention his dip in red zone targets last season. He saw just 11 red zone looks, down from 22 in 2012 and 21 in 2013, the year that saw Marvin Jones score nine red zone touchdowns. Sure, Cincinnati ran the ball more from inside the five and from inside the 10 than any other team last year, but Green is always a threat for top-10 red zone target totals unless the Hue Jackson mindset really does limit even a healthy Green in 2015. I would expect more than 11 looks this year, and that's coming from someone who's skeptical of his red zone potential.

Vincent Jackson, WR, Tampa Bay Buccaneers
Vincent Jackson saw 14 red zone targets last year and caught only three of them, though two were touchdowns. That catch rate (21.4%) ranked last among 50 receivers with at least 10 red zone targets last year. Jackson is better than that, and that's why he should have a bounceback season this year.

Kelvin Benjamin, WR, Carolina Panthers
Sticking in the NFC South but heading to the opposite end of the age spectrum, I have to mention that Kelvin Benjamin was super inefficient in the red zone last year. Benjamin caught just 4 of his 15 red zone targets in 2014. That conversion rate (26.7%) was better than only Jackson's among 10-plus-target receivers. Perhaps most amazingly, Benjamin, a 6'5", 240-pound receiver caught only three of his nine touchdowns from inside the red zone. There's reasons to expect an overall step back for Benjamin this year, but if a player built for red zone production actually converts on some of his targets, then he could be a lethal fantasy option this season.

LeSean McCoy, RB, Buffalo Bills
This one isn't as evident in the numbers as I would hope, but here we are. Based on volume, there's not much more room for LeSean McCoy to improve. He ran the ball 58 times in the red zone last year, tied for first among all running backs. However, he scored just four red zone touchdowns, a 6.9% conversion rate. The other two backs who saw 56 carries, Marshawn Lynch and DeMarco Murray scored 12 touchdowns, a 20.7% rate. Then again, McCoy hasn't had a rate better than 13.2% in the past three seasons. It's far from a guarantee, but McCoy will likely be better than he was in 2014 at least.

Colin Kaepernick, QB, San Francisco 49er
One reason I'd be perfectly contented going into the season with Colin Kaepernick as my fantasy quarterback is his red zone potential. Last year, Kaepernick ran the ball 15 times in the red zone, which ranked fourth among quarterbacks. Of the six quarterbacks to carry the ball at least 10 times inside the red zone, only Kaepernick and Tom Brady failed to score a touchdown. He had a combined seven touchdowns on 24 carries in 2012 and 2013, so I think there's plenty of reason to expect him to add some fantasy points on the ground this year.