Patriots lead Ravens at half

A handful of observations from the Patriots-Ravens first half:

* The Patriots haven't sat back against Flacco the way they did against Jets quarterback Mark Sanchez two weeks ago. Pressure got to quarterback Joe Flacco on back-to-back drop-backs early in the second quarter, including a hit from Mike Wright on a deep ball to Derrick Mason on first down.

Taking a snap out of the shotgun on the ensuing third down, Flacco underthrew a wide-open Mason off his back foot even though no one really was near him, and Brandon Meriweather caught up in time to swat the pass away. That's what pressure can do to a quarterback.

Then again, Derrick Burgess hit Flacco on the touchdown pass he threw to Mason in the first quarterk. But the amount of pressure the Patriots have put on Flacco is a good sign.

* The Patriots mostly have played in a 4-3 aligment in the first half, though they did seem to switch to a 3-4 set late in the second quarter. Along those same lines, Bill Belichick has rotated almost all of his available defensive personnel: New acquisition Terdell Sands even made his first appearance on the Ravens' third possession.

Sands doesn't totally have the hang of things yet, though. On one second-quarter play, Adalius Thomas grabbed him around the waist and shoved him to his left to make sure he was in the right gap.

* Wes Welker, playing in his first game since the season opener, has a team-best three catches for 29 yards and has shown off his signature elusiveness after the catch.

* Sammy Morris, relegated mostly to fullback duty in a backfield that includes Kevin Faulk, Laurence Maroney and Fred Taylor, has a key fourth-and-2 pickup and a 12-yard touchdown run to his credit.

* Roughing the passer penalties are the order of the day. The Ravens have been flagged for two -- a hit to the helmet and a hit to the knees -- and Wright was flagged for a blow to the helmet when he sacked Flacco in the second quarter.

* Leigh Bodden's toe-tapping interception along the sideline was the Patriots' first of the season. Bodden jumped a Mark Clayton route -- Flacco either underthrew the ball or Clayton ran the wrong route -- and picked it off, dragging both toes before falling out of bounds.

* Ray Lewis already has nine tackles. Ed Reed, so far, has mostly been a non-factor.

* Ravens tackle Jared Gaither was taken to Mass General for further tests on his neck and shoulder after a scary collision with Flacco. He did, however, have moment in all extremities.