During a recent UEFA Champions League match between Celtic (SCO) and Helsingborgs (SWE), Celtic #88 scored a goal from an offside position that was not flagged for offside.
But before we rush to criticize the AR, let’s take a look at the frame grab and see just how difficult it was to get this decision correct.
Play had been in front of the Helsingborgs (red) goal, when the ball was cleared to the top of the penalty area. A Celtic (white) player then played the ball to the left, to white #9 (who was onside when the ball was played). #9 is facing away from goal, and reaches back with his right foot to play the ball square to white #88, who then shoots and scores.
Since #9 was clearly onside when the ball was played to him (not shown in this frame), the only question to resolve is whether #88 was in an offside position when the ball was played to him. With the help of the orange line, we can see that white #88 is clearly ahead of the ball (and beyond the second last defender) when the ball was played.
What makes recognizing offside so difficult in this case is that the bodies of players #9 and #88 are in line with each other. Add to this the speed of play (fast) and one can see how difficult it is to get this decision right.
If I’m being honest, I likely would not get this decision right, certainly not at the speed of play of this game, and probably not even at the much slower speeds of youth soccer.