I was at the game on Saturday, so I decided to use my NFL Preseason Live to re-watch the game in detail.  Being a physical therapist, it's hard for me to watch a game without trying to see how an injury occurred to a particular player.  While watching, I noticed a play which I thought for sure was the play that Toler hurt himself on.  To my surprise, Toler was still in the game the very next play.  A couple minutes later thought, when I saw the actual play that the injury occurred during, I had to ask myself this question: Did Toler injure himself on an earlier play, decline to tell the staff about it, and end up with a worse injury because of it?  Hit the jump to see what I saw..

Here is the original play in question:

With around 7 minutes left in the 1st quarter, the Cardinals are setting up a defensive play on a 2nd &12.  The only problem is, Toler bites on a hard count and shows Rivers that a corner blitz is coming.  Rivers notices and takes action by calling an audible at the line.

This audible brings the outside receiver in close to get in the way of the blitzing Toler.  With little time to react, Toler starts looking around confused, not quite sure how he should alter his assignment.  As the ball is snapped, Toler hesitates slightly (could've been a stunt blitz), and starts in towards the QB.

Unfortunately for Toler, the LG (#68) was able to reach out (while blocking Porter with the other hand) and manage a little shove on the blitzing CB to alter his line and momentum.

This unexpected change in direction throws Toler off balance, leading to a very awkward fall.  However, Toler attempted to plant his feet to avoid falling over, to no avail.

This twisting fall looked extremely awkward, and is fairly consistent with the mechanical cause of a usual non-contact ACL injury.

Needless to say, after seeing Toler on the ground, I was convinced that this was the play that Toler injured himself on..

Of course, to my surprise, Toler was in on the very next play and so I shrugged and continued to watch the game. 

Somewhere around 2 minutes later in the 1st quarter, the Chargers faced a 2nd & 5, which for most teams means the RB is getting the ball.  Toler starts out way deep in the secondary, but starts creeping up towards the line in anticipation of the snap.

After the ball is snapped, Toler successfully diagnoses the run, and cuts in towards the middle of the field to help out.  As you can see in the next couple of screenshots, Toler makes this cut by planting on his left leg, which has fairly little bend in it.  Keep this part in mind, and I will explain the significance in a little.

Here's another view, a little bit closer.  Look at the position of his knee as he is making his cut.

It's my best guess that he blew the ACL out on that cut, mainly because he is already pulling up lame, and trying to avoid making contact of the pile of players in front of him.

And before you know it, there he is, clutching his left knee as the trainers come out to check on him and we get a commercial break..

Okay, so if I haven't lost you quite yet, good.  Keep reading.

It would seem to me that Toler might have actually tweaked his knee on the earlier play, but wanted to be a gamer and stay in against the high-octane SD offense.  He definitely didn't tear his ACL on that play, because he was able to continue.  However, if what I am thinking is the case, the actual ACL tear that has subsequently ended his season was more of a compensation injury that could have been avoided if he had notified the training staff and let them check it out.  Do I know this to be absolutely true? No, I'm just basing it off of what I know about ACL injuries, and a crappy quality replay video, so take it for what it is worth.

For those of you wondering about the significance of the position of the knee during Toler's plant and cut, watch this video first:

ACL Tear (Sports Injury) (via cityclinic)

Basically, when the knee is straight or only slightly bent (0-30 degrees of flexion), the ACL has the most tension through it.  Once a torsional (twisting) motion is added to the taut ACL, it has no more room to stretch, and ends up tearing.  In both instances, Toler was planting and cutting (or attempting to) with his knee in that extended position, rather than adding some shock absorption which comes from using one's hips and bending their knee more before cutting.  This may have been avoidable in the long run, but there's nothing we can do it about it now, except cheer on PP21 to be what we know he can be.
Hope you enjoyed this, hopefully it was at least semi-coherent.  If you have any questions, be sure to ask away in the comments section!