Constructing a strategy for the flex position in Apex Fantasy Leagues presents unique dilemmas for the owner that is accustomed to a more traditional roster construction. While most leagues roster either 2 RBs, 2 WRs, and a flex, or 2 RBs and 3 WRs, Apex leagues roster 2 RBs, 3 WRs, AND a flex.

Author’s Note: All data refers to PPR scoring.

In the traditional flex format, owners are looking for RB3/WR3 output (top 36 at either position in a 12 team league) when plugging in a flex. For Apex owners, borderline flex decisions often come down to choosing between an RB3 or a WR4. Intuitively, it seems obvious that you would want the position player ranked higher at their position (the RB3).  I dug into the numbers to see if we should ever target a top 48 WR over a top 36 RB.

Defining The Apex Flex

As I’ve already mentioned, when targeting a flex in Apex leagues, we want at least RB3 or WR4 production each week. In order to quantify RB3 and WR4 production, I looked up the fantasy output of RBs and WRs that finished ranked 25th-36th, and 37th-48th, respectively, over the last 3 seasons.

RB3 Averages, 2011-2013

 GamesRush AttYardsTDTargetsRecsYardsTDFantasy Points
Season Averages14.03151.89640.723.8639.4428.61229.44.78141.02
Per Game Averages10.8345.68.282.812.0416.36.0610.05

WR4 Averages, 2011-2013

 GamesTargetsRecsYardsTDRush AttYardsRush TDFP
Season Averages14.8191.8352.78704.254.781.9210.83.11152.67
Per Game Averages6.23.5647.

At first glance, you might see that WR4s have outscored RB3s on a Fantasy Points/game (FP/g) basis, and assume that the WR is the better choice. To ensure that the data isn’t skewed by top-heavy WR4s or really bad RB3s, we must set a baseline to compare the two positions and find out how many players from each position meet that baseline criteria. If one position outperforms the other, but the players aren’t available, then the data does us no good.

Flex Worthy Performances and Position Availability

Looking back at the average fantasy output from each position, we can take their combined average FP/g to set our baseline for a Flex Worthy Performance (FWP). In this case, that number is 10.18 FP/g. For consistency, I again went back three seasons to see how many RBs and WRs provided a FWP on a week to week basis.

RB FWP, 2011-2013


WR FWP, 2011-2013


To fully understand these numbers in context, we have to consider how many players at each position provide a FWP and are available for owners to insert as their flex starter. To do this, we have to look at how many FWP/Week are available in excess of Apex starters. Recall that Apex rosters require 2 RB and 3 WR, and leagues consist of 12 teams, so each league starts 24 RBs and 36 WRs each week.

While on any given week we can expect, on average, a surplus of 6.67 FWPs, 4.15 of those games are going to come from WRs, while just 2.52 RBs are going to be worth a flex start outside of the top 24.

One last note should be made when comparing RB3s and WR4s. If we revisit our season averages for each position, one might argue that RB3s get more opportunities (Opportunity = Rush Attempts + Targets) to touch the ball, so they are still a better play than WR4s. If we look at FP/Opportunity, though, I’d still choose the WR4’s 1.63 FP/Opportunity to the RB3’s 0.74 FP/Opportunity.

Applying FWP

No fantasy owner should look at these numbers and blindly plug in a WR at their flex every week. We should, however, recognize that in deep roster formats, there are many times when the player pool is scarce and we are forced to start some mediocre players. When we do find ourselves in a coin flip situation between middling players, we can look at the numbers and trust that, over the long-term, our borderline WR is going to outperform the RB almost twice as often.