As it turns out, it WAS a touchdown for Troy Polamalu, but it’ll never show up that way in the history books. Fortunately, this error didn’t change the outcome of the game. However, it messed up a lot of gamblers and fantasy players, and could possibly affect the playoff picture under certain scenarios.
The problem is that if ANY forward pass touches the ground, the play is dead. The officials simply got confused about which pass was which.
The little flip pass from LaDanian Tomlinson to Chris Chambers was an illegal forward pass, but was handled cleanly by Chambers. When Chambers tried to lateral again, the ball hit the ground. However, because that pass went backwards, the ball was still live and it was legal for Polamalu to pick it up and score.
There still should have been a penalty on the Chargers for the illegal forward pass from Tomlinson, which the Steelers could decline so they could keep the touchdown. That’s what happened initially. After that, referee Scott Green changed his mind (got confused, etc) and things got a little weird.
As a result of this mess, the NFL is looking at making some slight tweaks to the replay system. With the new rules, officials will be allowed to re-review a play if they think they need to. This new system could be in place in time for the playoffs.