Whilst on first viewing I thought the red on Shephard looked harsh, on second viewing, I don't think it will be rescinded.
I showed the footage to my colleague who is an ex referee and he said the key thing to look at it is the footwork and the position of the elbow. Whilst initially it appears Carey runs into the Peterborough defender, if you watch the defenders feet closely, he actually makes a purposeful step back, into the path of Carey, which more importantly is "unnaturally" away from the ball, which is going down the line to Sawyer. So in the first instance, it is a foul for a block.
Then, the matter of which colour card. Watch the left arm / elbow of Shephard. It's hard to see from the angle of the television cameras, as it is partially concealed by the player, and is done so rather shrewdly as for the referee not to see, but the elbow is indeed raised to coincide with the body check on Carey. In fact it seems as though it is the linesman on the far side of the pitch who has spotted the elbow/block, rather than the referee. So, whilst it may certainly be harsh, by the laws of the game, it is a red card, and I expect the decision to be upheld (as the Wyke red card for Bradford was).
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