Johnson's Back Spasms
He was asked what he thought caused it.
He said he didn’t know but said that he thought it was odd in that it was only on one side and came on suddenly.
People can go back and re-watch the game. Go to the second quarter just before he left with the injury.
You will notice that he was posting up and Gasol had his right forearm pressed against Johnson’s back. A lot of defenders do this because it is legal and a foul won’t be called for it.
However what happened next was that Gasol’s right forearm became removed from contact with Johnson’s back. Then Gasol forcibly shoved his right forearm into the location where Johnson was injured. Immediately after the forearm shiv to Johnson’s lower back he had to come out.
Maxiell used this tactic on Howard a number of years ago in the playoffs with similar results. Howard was hampered for the rest of the playoffs as a result.
It is not too difficult to injure someone on the lower back using a forearm shiv if you know what you are doing and where to hit the other person in the lower back with your forearm. Johnson and Gasol were going at it pretty good and frankly in the first quarter Johnson got the best of the battle so it wouldn't surprise me that Gasol may have been dishing up some payback for that.
On the other hand in the heat of battle a player can just be playing hard defense and sheet happens. That is what I think happened here Then again I am a big Pau fan so I would be inclined to give him the benefit of the doubt in situations like this.