How Does Age and/or Workload Affect RB Health?
We hear it a lot this time of year: "I know he finished in the top 10, but I'm worried about ________'s workload in the last two years. Plus, he's 30 years old. He's going to break down."
Heading into the 2013 season, this sort of discussion seems to revolve around Arian Foster (workload) and Steven Jackson (age), so let's see how those two factors play into the most important stat in fantasy football: games played. (Unfortunately, it's also one of the toughest to predict.)
Starting with rookies in the 1990 season, I tracked the age, touches and games played for the 184 running backs who finished in the top 36 (i.e. fantasy RB3 or better) in at least one season during their careers. The first thing I looked at was...
The conventional wisdom is that running backs hit the wall at age 30 and as the chart below shows, that's generally true.
Keep in mind that the average games played for all fantasy-relevant running backs was 13.2 games. So, all else being equal, a fantasy owner should expect to get 13-14 games out of his running backs.
The chart shows a slight decline from age 22 to age 29, but once a RB is on the wrong side of 30, his expected games played falls to the 12-13 range until the age of 34, when it drops even further.
So this is bad news for Steven Jackson, who turns 30 in July, right?
Let's look at...
I had to decide if I was just going to look at carries, or include catches as well (carries + catches = touches). I went with touches since an RB is asked to make a move when he catches the ball and most catches end with a tackle.
Is there some sort of breaking point that is (reasonably) consistent for all backs? To find out, I tracked total touches in previous seasons along with games played the following year.
Interestingly, the average games played has a negative correlation with career touches, but once we get to the group of backs with at least 2,000 touches, the correlation seems to turn positive to a peak of 14.1 average games for running backs with 2,500-2,999 touches.
Why would this be?
To get an idea of the type of players we are talking about, here's a list of RBs that were able to amass that many touches since 1990: Edgerrin James, Emmitt Smith, Jerome Bettis, Curtis Martin, Marshall Faulk, LaDanian Tomlinson, Jamal Lewis, Eddie George, Fred Taylor, Thomas Jones, Corey Dillon, Warrick Dunn and Ricky Williams.
Steven Jackson heads into the season with 2,802 touches so he fits squarely into this group. To reach the 2,500-touch milestone, a player has to be productive, relatively healthy and professional. Aside from a few exceptions (Fred Taylor, Jamal Lewis, Jerome Bettis and Marshall Faulk), this group stayed relatively healthy into their 30s, helping the subgroup post the highest average games played.
But what about the over-30 crowd?
Yes, those 2,500-plus touch RBs who are over 30 haven't stayed as healthy as the under-30 crowd, but their 13.4 average games played is still better than the overall average (and better than the average games played by under-30 players with 500-1,999 career touches).
So from this perspective, fantasy owners should not be afraid to draft Steven Jackson.
Last Year (LY) Touches
I also wanted to see if a high workload in recent season(s) had an impact on games played the following year. Take a look:
Interestingly, it does have an impact -- a positive one! Notice how the 300-plus groups averaged more games in subsequent seasons than the under-300 groups.
Note: When I broke down the 250-299 group further, I found that the 275-299 backs averaged 13.3 games played while 250-274 backs played 12.7 games. More on this later.
With regard to the yards-per-carry argument against Foster (that his YPC has dropped in the last three seasons), please see Jonathan Bales' article on the subject. I believe that Foster is still nearly the same back he was two seasons ago, but the Texans' offense has been so run-heavy that defenses have adjusted. The team's decision to draft DeAndre Hopkins in the first round indicates that the Texans realize they have to develop more of a passing game to help open up running lanes for Foster.
Last Two Year (L2Y) Touches
Going a step further, here is how the total touches for the last two seasons relates to games played the following year.
Again, we're seeing relative dependability from the 600-plus touch group, with a slight decrease as the touches approach and go over the 800-touch mark. Still, those players who amassed 800-plus touches had a better than average games played than the RB position as a whole.
How does this impact our two running backs, Jackson and Foster?
Jackson had 295 touches in 2012 and 597 in the last two seasons, while Foster had 391 and 722, respectively. Based on my findings, the recent workload for these two players raises no red flags.
Recent Injury History
In my years of experience crunching numbers, I've found that the best indicator of any given statistic is generally the statistic itself...from previous years. With that in mind, I tracked the average games played in the previous two seasons and compared it to the games played the following year.
The first group (15.5-16.0) includes RBs who have stayed healthy for the last two years, allowing for one missed game due to Week 17 rest or minor injury. As a group, these are the RBs most likely to play the most games the following season. This group includes Steven Jackson and his 31 games played in the last two seasons.
The next group (14.5-15.0) accounts for 2-3 missed games in the last two seasons, so these are players who have experienced minor injuries that have knocked them out for a game or two in each season. Or in the case of Arian Foster, three missed games in 2011 and a full slate of games in 2012. Since he is under 30, we can expect him to play at least the league average in 2013.
The dependability of these first two groups might explain why the group with 275-299 touches (from the note above) played more games the following season than did the 250-274 group. If the player is dependable in year Y, he should be dependable in Y+1. And more touches typically equal more dependability.
Moving down the line, it's clear that the over-30 crowd doesn't seem to bounce back as well from missed games in recent years as the under-30 group does. For the most part, an under-30 player can be expected to play the league average (13.2 games) when coming off 1-7 missed games in the past two seasons.
Should fantasy owners shy away from Arian Foster or Steven Jackson due to workload or age concerns? I don't think so. There's always the chance they go down for a stretch of games or even suffer a season-ending injury, but that's true for any RB -- young or old, rookie or grizzled vet.
Owners worried about drafting Foster should secure Ben Tate as his handcuff. Since Tate himself missed five games in 2011, he doesn't seem to be going quite as early as he has in years past. If I only have two good RBs on the roster, I might use an 8th/9th round pick on Tate, but if I feel good about my group of 3-4 RBs, I would probably wait longer to draft him since I already have coverage if Foster were to go down.
As for Jackson, Jacquizz Rodgers is the clear backup and he can be had in the later (11th-12th) rounds. I really like Jackson as a low-end RB1/high-end RB2 with his move to Atlanta. Michael Turner had almost twice as many red zone carries as Jackson last year, so I believe 10-plus TDs are likely for S-Jax...
As long as he stays healthy.