The Pats subbed in a largely fresh line for that play...big bodies to jam up the line. Yes, Lynch was doing better in the second half, but he never dominated...and at 1-2 yards to go he was stuffed several times. Prior to the bobble play, the Patriots defense had held Seattle to 3 3-and-outs.
The Pats had two defenders on the side of the field where the pass was, with one of them occupied with a block. The Seahawks got the matchup they wanted, it just didn’t work...apparently because Butler was burned for a TD on the same play during a scrimmage this week with the scout team, and Belichick burned it into his brain. Butler didn’t even look at the defender.