That would make sense if there wasn't a surfeit of quality corners on the market.
Indeed. But the majority of logical fits for the Patriots are already off the board for various reason.
Just off the top of my head:
• Chris Gamble, retired
• Sean Smith, signed with the Chiefs
• Keenan Lewis, signed with the Saints
• Sam Shields, tendered by the Packers (2nd round)
• Dominique Rodgers-Cromartie, signed with the Broncos
Those corners all possess legit #1 CB ability. That basically leaves the aforementioned Talib, Nnamdi Asomugha, and Brent Grimes. All three of them carry significant risks in their own right. Talib has injury and character concerns. Asomugha has age, desire and declining skills issues. While Grimes also has injury concerns. Do you think it's wise to lock up either of those players in the $4-6M range after just giving $4M to Arrington. That's seems like a awful lot tied up for players with obvious risks, in my opinion.
The Patriots could always go after rapidly aging and declining bargain basement JAGs like DeAngelo Hall, Sheldon Brown, Terrence Newman, Quentin Jammer, etc. Though they may end up having too anyway, if Talib doesn't come around.