Westwood is striving to become the first to win the US Open the week after a PGA Tour victory
Lee Westwood insists he is still very much in contention as he chases a maiden major title in the 110th US Open at Pebble Beach.
The world number three added a level-par 71 to his opening 74 to reach halfway three over, six shots behind leader Graeme McDowell.
But fresh from his first PGA Tour win in 12 years last week, Westwood still believes he can challenge on Sunday.
"Three over going into the weekend isn't a bad position," he said.
"I didn't get any momentum going either day but you can't attack a US Open course, you have to play patient golf and once you've done that you know you just have to hang around and not be too aggressive."
The 37-year-old world number three has finished in the top three in the last three majors and missed the play-off by one shot when Tiger Woods beat Rocco Mediate to clinch the 2008 US Open, but no-one has ever won a US Open the week after winning on the PGA Tour.
"I don't think anybody's going to run away with this," added Westwood, who could theoretically overtake Phil Mickelson as world number two this week.
"It's that type of golf course and gets harder as the day goes on. So I still fancy my chances."
Casey notched up an eight on the treacherous 14th at Pebble Beach
England's world number nine Paul Casey, the joint first-round leader, was still the highest placed Englishman going into the weekend after carding 73 to finish level par.
Casey's round included a triple-bogey eight on the par-five 14th but the Arizona-based star was content with his position."I'm completely fine with where I'm at and I don't feel like I've got to do anything out of the ordinary, just stick around par, see what happens," he said.
"I do like my position but it's about eliminating mistakes and I've done a pretty good job of that.
"Graeme is three under so there's a lot of golf left yet. Maybe there's some more treacherous 14th holes to contend with and who knows what happens.
"I mean, I feel like I played very good golf over two days and I've racked up some birdies and racked up a big number as well.
"So anything's possible. We've got a long way to go."
Wales' Rhys Davies, who won his maiden European Tour event in Morocco in March and had consecutive runner-up finishes at the Madrid Masters and Celtic Manor Wales Open, improved on his opening 78 with a one-under 70 to go into the weekend at six over.
"That was more like how I play golf today," Davies said. "I struggled yesterday and I expected to play well but didn't and as a result it felt worse than it was.
"Today I knuckled down and played okay, not great. I fought it out and my short game was really good and kept me in there."
McDowell's Northern Irish compatriot Gareth Maybin will join him in the weekend's final rounds having made the cut on the number at seven over thanks to an eagle at the 18th to close his second round.
The Belfast golfer made three on the famous par-five after hitting a rescue club from 235 yards to around 15 feet from the flag and one-putting from there for a 75.
"I knew I had to do something special to even have a chance of making the cut," Maybin said. "So I hit driver off the tee and hit a pretty good rescue in there to about 12 feet and I was fortunate enough to make the putt."