The Englishman, who was 0-2-2 in Europes 16 1/2 -11 1/2 loss to the U.S. last weekend, shot a 2-under 70 to reach a 6-under total of 138 after a three-hour delay, with half the field set to complete the round on Saturday.
Westwood, who opened with a 68 Thursday, led by two strokes over former British Open champion Paul Lawrie, who shot 71.
Graeme McDowell'the only other player from the European team'shot an erratic 75 and could miss the cut after the second round is completed.
I made a few mistakes, Westwood said. I still feel a bit tired, even more today than yesterday. I got off to a poor start, just dropped a couple of silly shots.
But all in all it was pretty good and Im pretty happy.
Westwood played the back nine first, shooting a 1-over 37, then birdied the first three holes after the turn.
I knew I had to play the holes on that nine strong and managed to birdie the first three of them, Westwood said.
McDowell was 2-1-1 in his first Ryder Cup.
I gave it 120 percent and had a lot of personal satisfaction from it. But now I have to get ready for the rest of the season, he said. I have to learn how to recover from things like that.
Colin Montgomerie shot a 3-under 69'an improvement of 12 strokes over his opening round'but still missed the halfway cut.
Lawrie is struggling with his game but was encouraged by his 71 despite a bogey at the last hole.
Ive putted a little better this week because the greens are very good, said Lawrie, who won the Open at Carnoustie in 1999.
One of the two overnight leaders, Mikael Lundgren of Sweden, shot 75 to slip down the board at 2-under.
The other, Marcus Fraser, was a late starter and will finish his round Saturday.