Keep and eye on ...
How Cassel responds after bye:Matt Cassel led the Patriots to a win in his first start in Week 2 against the Jets but struggled in the loss to Miami. Cassel has two things working in his favor: He had extra time to prepare during the bye and the 49ers allowed Drew Brees to throw for 363 yards and three touchdowns last week.
The pressure put on O'Sullivan: Defenses attack Mike Martz's offense by pressuring the quarterback. J.T. O'Sullivan has been sacked 19 times in four games and he's lost three fumbles. The Patriots have just six sacks in three games, two apiece by hybrid pass rushers Mike Vrabel and Adalius Thomas.
The effectiveness of Gore: Running backs have excelled under Martz, and Gore has gained at least 99 total yards in each start this season. The Patriots rank in the bottom third in total defense, and their run defense, ranked 25th, has been gouged so far for more than 140 yards per game.
Did you know?
The Patriots are jusy 10-9 after bye weeks ... This is the Patriots' first trip to San Francisco since 1995. ... New England has not lost back-to-back games since Weeks 9 and 10 in 2006, losing to the Colts and Jets. ... 49ers wideout Isaac Bruce ranks fifth all-time in the NFL with 953 career receptions, moving past Andre Reed (951). ... 49ers kick returner Allen Rossum leads the NFC with a 29.6-yard average.