I thought you knew a ton about football. The line judges job is to be on the sidelines on the same side as the chains; set up the chains for a first down, watch for illegal procedures, and run with WR during pass plays. An UMPIRE, stays in the middle of the field 3-4 yards behind the defensive line. They can line up anywhere in the middle of the field and most, like this guy, line up opposite of the referee from the middle of the field to the hash mark.
It does look like he was doing his job. The game play is so much quicker than most people can imagine and by the time Garcia got up on him he couldn't really move out of the way and just protected himself.