I'm a huge McCourty fan, so I'm really hoping he re-signs. And I was probably one of the few who was against Revis coming to New England because I thought he'd be a selfish diva. Obviously totally wrong about that and he was a great addition and I don't think we win the Super Bowl without him.
I took a look at the past few years to see the potential impact on our pass defense. Obviously it's a flawed exercise because players have changed, roles have changed, guys have progressed/regressed, but FWIW:
2012: 271.4 YPG (29th), 27 TDs, 20 INTs, 86.9 Opposition QB Rating
2013: 239.0 YPG (18th), 25 TDs, 17 INTs, 81.0 Opposition QB Rating
2014: 239.8 YPG (17th), 24 TDs, 16 INTs, 84.0 Opposition QB Rating
2012 was rough, but it got better after we traded for Talib and moved McCourty to safety. While it's tough to tease out who had the bigger impact, the 2012 split is worth mentioning:
2012 (9 games before Talib trade/McCourty move)
285.3 YPG, 18 TDs, 11 INTs
2012 (6 games after Talib trade/McCourty move)
260.8 YPG, 9 TDs, 8 INTs
Talib didn't play the last week so excluding it for now. In case you're interested, the secondary did great against a terrible Dolphins passing attack so you can take that as proof of McCourty's value, or say it's too small a sample size to bother. You can also dismiss the second half improvement due to coaching, as our teams tend to improve as the season goes on. Nothing is absolute here.
But we can see a significant improvement in 2013 from a full season of those two upgrades.
The Revis signing in 2014 improved us, but it wasn't a massive leap over the team with Talib, and part of that might also be due to Talib missing 3 games in 2013. But having an elite corner paired with the position switch for McCourty was a big improvement over 2012. So losing both could be pretty significant.
We were fortunate to have an elite corner in Revis fall into our laps to replace the elite corner we lost in Talib. I don't think we can count on that happening again next week because the Bucs don't have anyone left to give away.
My guess is their first goal is Revis, and if the price gets too high, McCourty is the fallback. Ryan should get minutes at whoever we can't replace, and Butler will also get a chance to take over a top CB role.
BTW, Talib's 4 games that he missed were mostly against crappy QBs so I'm not putting much stock in this. But FWIW, those 4 games with McCourty and no Talib/Revis looked like this:
2012/2013, 4 games: 3-1 based on 2 wins over the Dolphins, 1 win over the Steelers, and a loss to the Geno Smith Jets?!?
232.8 YPG, 7 TDs, 6 INTs
Most of the damage done by the only competent QB on that list. Big Ben threw for 400 yards, 4 TDs, and 2 INTs in a close game until the 4th quarter, when the Patriots dominated 28-7 to turn a 27-24 game into a laugher.
So we could potentially look decent with McCourty alone, obviously not as good as with Talib/Revis/other elite corner involved, but not awful either.