Questions/discussion on position substitution frequency

Submitted by DualThreat on August 16th, 2017 at 4:46 PM

As someone who is not an expert in all things football, I'm curious how often various position groups of a football team get substituted.  I thought others might be curious too, so alas, this topic.

What sparked this thought is the matchup against Florida and what we all know is a killer starting defensive line, but possibly some significant drop off after the starters.  So, how long do defensive line starters typically stay on the field until they get a breather?  Is it a few plays?  A few series?  A whole quarter?  Does it just depend on the coaches watching them play and noticing when they seem tired?  How long do they typically sit?

Similar question for other position groups.  It seems that QB, P, K, and sometimes RB play a whole game, but what about others?

I've always been facinated by the strategy of football.  Similar to a car race pit stop, I'm sure there is some optimization to be had regarding subbing as a group vs. individual subs and when to do it for various position groups.

Thanks in advance for feeding the football appetite while we wait 10 days for the season to start.





August 16th, 2017 at 4:56 PM ^

DL starters will usually rotate anywhere from every 2-3 plays to 7-8 plays depending on depth, situations, sub packages, and tempo. Ideally it would be every 4-5 plays probably, but as Brian mentioned earlier this week, the 2011 line got by playing Roh, Martin, and VanBergen like 75-80% of the time.

Receivers and running backs rotate quite a bit. LBs do if depth is availible, but some do play the whole game. Secondary, OL, and QB usually do not rotate.


August 16th, 2017 at 5:39 PM ^

DL tends to rotate quite a bit, as you said, especially if the offense huddles and gives you a chance to play your run stopping or pass rush specialists, on running or passing downs.  

For no huddle offense, rotations tend to be drive based (every drive switch or two on for starters, one for backups, etc) rather than play based.  And then if you have guys that are beasts against the run and pass, you roll with them as much as they can handle, especially if there's a dropoff to backups.  

I imagine we'll see Gary and Hurst going 75-80% of plays this year, at least, and they'll likely rotate some along the line (Gary at 3-tech and Hurst at NT on passing plays).

Totally agree with your other position comments.  TEs/FBs/blocky catchy types rotate quite a bit too depending on running/passing situations.


August 16th, 2017 at 5:01 PM ^

Say an incomplete pass on second down results in a third and long. A defense might be more likely to go with a pass rush focused front four (for example, moving Gary inside and using, say Vilain as a rush end).

The same could be true for games against more power run focused teams, such as Wisconsin, where a Viper type might be more of a negative, you're more likely to see a bigger, traditional B1G linebacker, at least for stretches. 

Then obviously you have known quantities, like a third down back, whose job it is to specifically come in and either catch the ball out of the backfield or pass protect. 


August 16th, 2017 at 5:07 PM ^

I've often believed that there is a fine line between too much or too little substitution. I like to think there is a strategy to creating beneficial mismatches, even if just to confuse your opponent with uncertainty. I'd like to see modern football develop into a system similar to hockey, with line rotation being designed to maximize energy / skill. I would prefer a rotation with another athlete at full energy but 90% effectiveness over a proficient athlete at 75% energy any day. This depends a lot on position group and specialties, but can also lead to more experience for younger players, less injuries from playing fatigued, and a strategic advantage over your opponent.


August 16th, 2017 at 5:33 PM ^

OL - Never unless injury

QB - Never unless injury

TE - Starter probably gets 80% of snaps (Harbaugh's offense is a bit unusual)

WR - 2 starters will play the majority of snaps. Different formations will let 3rd and 4th WRs on the field. 

RB - Anywhere from every snap to rarely. Pretty common to have a different "3rd down" back with a different skillset for pass protection and catching screens and wheel route passes.

S - Almost never

DB - Almost never. Nickel corners come in on some packages.

LB - Almost never. SAM vs spacebacker type might rotate depending on down/distance and game situation.

DL - Probably every set of downs is pretty common if you have a lot of guys that can play. Again, you might have pass rush specialists come in on certain down and distances. Against slower paced teams you don't need as much substitution. Hurry up teams you need more and it's harder to sub because lots of times you only get to substitute if the offense does.  



August 16th, 2017 at 7:05 PM ^

I've always wondered about the Offensive Line.  I know nobody ever rotates them or changes personnel.  Maybe they do the occasionall 6th OL for obvious goal line packages.

I guess my question is:  "why not?"

Are DL snaps that much more tiring than OL snaps and thus it doesn't matter in terms of freshness & stamina?  Is it just the difficulty/folly of burning enough scholarships to ensure a pipeline of solid OL players to the point where you could competently field TWO solid lines?

Because it seems to me that along the line, at least a FEW of the D1 programs by now would have experimented with fielding a rotating OL not unlike a rotating DL or even a hockey "line" system.  Not rotating on each play, but maybe per series.  That way, your starters remain fresh into the 4th Quarter (no Onwenu issues), and you may even be able to totally screw up the opposing defenses if one of the lines specializes in a different blocking scheme.  i.e. zone/gap/man.

Maybe it's just the difficulty & impracticability of getting 10 dudes up to the right size/competency given the limited scholarship numbers.  But even if you didn't do a full 10 man "two-line" rotational system, I am a bit surprised that OTs aren't switched in or out for obvious passing downs like the DL.


August 17th, 2017 at 1:29 PM ^

OL play is a choreographed movement between five guys.  DL play is typically each player attacking a single gap.   Advanced DL play can involve a little choreography with stunts and what not.  But typically OL is more analytical/physical while DL is more decisive/physical.  What I mean by that is that OL will process the play before, during, and after the snap reading what the DL and LB are doing and adjusting his choreographed steps accordingly, for a play to be successful all five OL have to be on the same page with these adjustments.  While DL will typically make a decision very quickly based on reading the offense and attack.  DL have to determine is it a run or pass, are they trying to reach me, trap block me, double team me, etc. all within miliseconds after the snap and then attack accordingly. 


But as to why DL rotates, the answer is double teams.  DL are constantly double teamed by two ~300 pound men.  OL are never double teamed so they don't gas out as quickly.  Getting hit by 600 pounds play after play, especially when you don't know with certainty where it will come from wears on you physically and mentally.  OL always know who they are going to hit and are rarely overmatched physically.  In the rare case they are overmatched in a one on one they are supported by backs and tight ends who can chip and help out in pass pro.  


August 16th, 2017 at 5:52 PM ^

I feel like most of the better coaches these days rotate their RBs. I assume that's mostly so there's less wear & tear on one guy, but some ancillary benefits would seem to be that you get more guys ready in case of injury to your #1 and also you could have specific plays or packages to best utilize a particular back's abilities.

Mr Miggle

August 16th, 2017 at 6:34 PM ^

on substitution patterns. It's hard to make situational adjustments on the DL and LB. They are also prompting more teams to utilize a player like our viper position. Previously we had seasons where we were in the the nickle more often than we played 3 LBs. Nickles are most often a third CB, not a hybrid LB/S like Khaleke, so the risk of being stuck in a mismatch is a problem.

It also seems like we see more TE rotation nowadays. There are more flex TEs which leads to more situational subbing.


August 16th, 2017 at 7:16 PM ^

This is reminding me of 2015, when Glasgow got injured.
OSU waited until the new backup, Godin, rotated in, then went tempo (preventing him from getting off the field) and overpowered him over and over.


August 16th, 2017 at 10:06 PM ^

Should Michigan have done something different in that situation?  I know some teams (LSU?) have been accused of having players fake injury to slow the game down and allow a substitution in those situations.  Barring that, is there something we should have done differently?  I assume it would be a very rare situation that would warrant a timeout for this, but not inconceivable.  Any insight appreciated.


August 16th, 2017 at 9:38 PM ^

Thanks for the feedback all!  This board is a wealth of knowledge.

I had no idea DL was rotated that much more than other positions.  Interesting.  I'll have to keep an eye on that more next time I watch a game.


August 17th, 2017 at 8:43 AM ^

I am a defensive assistant at the varsity level in high school and I can tell you that I try to rotate my interior guys ever 3-4 plays. My defensive ends will rotate less frequently. 

I will also bump my ends inside in some situations. It really all depends on the situation, etc.

Obviously that is high school and we don't have the advantage of having 6-8 plus-players that can be rotated every 2-3 plays to stay fresh. 

Linebackers will rotate much less frequently and the secondary even less frequent than that. But again, in a perfect world, every team will have packages based on the situation.