Who will sustain a fantasy spike?

Stevan Ridley posted 1,314 rushing yards for the New England Patriots last season. Winslow Townson/Getty Images

It's rare that I get to jump into the fantasy realm, but 'tis the season, and this doubles as a look at key fantasy players and an education in just how hard it is to predict sustainability. If you think of the times you've won a fantasy league, your final roster was almost surely an imperfect blend of (A) guys you relied on who lived up to expectations, (B) good health and (C) a couple of players who outperformed expectations by a fair margin. Think of Sidney Rice in 2009, Jamaal Charles in 2010 or Jordy Nelson in 2011. Each could have been the difference (I still love you, Jamaal) in a fantasy winner; a late-round grab that performs to the level of an RB1 or WR1.

In each of those cases, however, we saw a player who could crush you the following season if you bet too big. Rice got dinged and fell off by over 1,000 yards; Charles got hurt in Week 1 and was out for the year; Nelson dipped by 25 catches and over 500 yards. With that in mind, where do you have Reggie Wayne this year? Was the leap from Curtis Painter to Andrew Luck the difference, or do you assume a dip for a 34-year-old who just spiked in totals by about 40 percent?

Let's make some predictions on the 2013 Spikes class.

A few rules:

1. Players must be ranked within the top 20 in yardage by position for 2012. Yardage is a better indicator balance of real and fantasy performance than the alternative, which is total fantasy points. It better incorporates usage. Points can be skewed by bad luck on touchdowns (and TD vultures). Consider Calvin Johnson in 2011 versus Calvin Johnson in 2012. The 2012 version might have been a better receiver, but had bad touchdown luck. (The Lions really should have a statue of Megatron being tackled at the 1-yard line to memorialize their 2012 season.)

2. Spikes must top 20 percent. Meaning the yardage jump was at least 20 percent more than the previous season.

3. No exceptions for injuries … except at QB. Health is an NFL skill. Just as you choose fantasy players based on a track record of health, teams value them based on their best assumptions of health. But at QB, only Sam Bradford, Matt Schaub and Carson Palmer saw yardage spikes of 20 percent or more in 2012, and Bradford and Schaub jumped purely on health, Palmer because he actually played football. (Colin Kaepernick doesn't qualify based on No. 1 and almost No. 4.)

4. No rookies. There must be a previous NFL performance from which a player can spike.

With that said, let's take a look.

Running backs

The running back yardage combines total running PLUS receiving yardage, just as it does in fantasy football.

Jamaal Charles

2012 yards: 1,745 | 2011 yards: 92 | Spike: 1,896.7%

Sustainable: No. Three reasons. One, last year Charles carried the ball 280 times. That total is 50 carries more than his previous career high (2010). Two, new head coach Andy Reid has never had a runner carry the ball more than 280 times, except for 1999, when Duce Staley did during Reid's first season in Philadelphia -- that team went 5-11. It's notable because Reid from there basically coached winning teams, and didn't allow a runner to pile up a ton of carries even as his team milked leads. He simply loves to throw the ball. Third, the Chiefs drafted Knile Davis to help take some of the load off Charles who, while a brilliant runner, should never be confused for a 300-carry workhorse. If healthy, Charles should get close, but I wouldn't assume he'll top his 2012 total.