Much has already been written about Kyle Shanahan's sideline outburst during this past Sunday's game against the Seattle Seahawks. The refs hit the San Francisco 49ers head coach with an unsportsmanlike penalty following his passionate response to his defense being flagged offsides. If you haven't seen Shanahan's outburst yet, you can watch it here.

It turns out Shanahan was upset that Seahawks quarterback Russell Wilson had thrown Fred Warner's shoe, which delayed the 49ers as the rookie linebacker tried to recover it. Shanahan said the penalty was the "icing on the cake" and the "tipping point" for him.

"It was definitely a number of other [questionable calls] from earlier that was a build up," he added.

Shanahan made it a point to state that he doesn't know if Wilson's actions were malicious but only that it created an unusual situation.

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Defensive tackle DeForest Buckner was on the field for the 49ers at the time and witnessed what television cameras failed to catch. He joined KNBR on Wednesday morning and described the situation from his perspective.

"It was on the play where the sack that should have been counted but (the refs) counted us offsides," Buckner said on the "Murph & Mac" show. "Fred's shoe came off and [Wilson] grabbed his shoe and chucked it like 10 yards behind their line of scrimmage. He made his whole offense get on the ball and snap the ball real quick.

"We didn't have enough guys on the field. We had guys trying to run on the field for Fred, and we got called for offsides or something like that. It should have been a dead ball. The referees should have called it."

Buckner does admit that fans and the local media probably would have praised quarterback Nick Mullens had he done the same thing.

You can listen to the entire conversation with Buckner below.