I'm having a hard time blaming Leavitt on the play. I've been watching the replay and it looks like he was left with two men to block. The Vikes had a stunt called and two men came through. Leavitt took the inside rusher (which is pretty much always the right call) and the wider/second man won.
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I've only watched the above a few times, so someone else could correct me. It looks like part of the stunt was a delay, which pulled the right guard (McDuffy) wide, creating a natural gap.