They aren't going to field a team of all pros. If Simon can make the position switch and High rest a bit, they might have enough LB strength. I think we've got lots of strength at DBand some latent strength at DE/OLB without Simon.
It's not really a position switch for Simon to play off the ball. He's been an OLB/DE in 3-4 defenses with BAL, HOU and IND, playing something like the old "elephant" role from the Pats' 3-4 under Crennel. While Simon is not exactly WillieMac , he does appear comfortable in the role.
In his Pats debut v MIA (wk-4), he set the edge well, had 5 tackles and a sack. Last night, playing only 13 snaps in his first game back after injuring his shoulder against Indy (wk-5), he had 2 tackles and what I thought was a shared sack, although it wasn't officially scored as such.
Anyway, he seems like he can be a versatile chess piece on the edge for the Pats. With Simon, KVN, HT, Flowers, Wise, Davis and Rivers, the Pats now have a cupboard well-stocked with guys who are at least competent playing the edge, and in a variety of roles - enormous change from last season.