Adam Scott remained in a share of the lead but things became bunched at the top in the World Golf Championships-Bridgestone Invitational at Akron's Firestone course.
Australians Scott and Jason Day, who kicked off with superb rounds of 62 and 63, both shot 70.
“Well, obviously I had a lot of momentum yesterday and seemed to find my rhythm off the tee and into the greens and on the greens,” said 31 year old Scott.
“But today was a little tougher. I started really solid, but couldn't make anything on the front nine.
“And then I just hung a couple drives out to the right, so I was in the rough and scrambling a little bit coming in.
“But it was fairly solid golf, other than that. It was fairly solid other than that; 70 around this golf course is never really that bad. So hopefully I can hit a few more fairways over the weekend.”
Scott is now part of a four-way tie for the halfway lead with Americans Rickie Fowler, Ryan Moore and US PGA Tour rookie Keegan Bradley, playing the first WGC event of his career.
Scot Martin Laird is just one behind with Day and Swede Robert Karlsson, but it was an afternoon of frustration for Lee Westwood.
England's World Number Two threatened to be the story of the day when he moved from three under to six under, but he then covered the last six in four over and was slinging clubs back to his bag by the close.
In contrast, Rory McIlroy came home in 33 to climb to four under with another 68 and world number one Luke Donald's 69 put him one further back.
Laird produced the sort of finish that Westwood would love to have had.
The 28 year old newlywed - he was married last Saturday in Colorado - birdied the final three holes to add a 67 to his opening 66.
Laird said: "I came into this week feeling fresh and on a high. Sometimes and it's amazing when you have no expectations how well you'll play."
Laird, winner of the Arnold Palmer Invitational in March, had mixed three birdies with three bogeys as he came to the long 16th, but struck an 83-yard pitch to four feet there and closed with putts of seven and 15 feet.
Round of the day came from 22 year old Fowler, a 64 containing an eagle two - he sank his 109 yard pitch to the third - eight birdies and four bogeys, including one at his final hole.
“I hit two perfect shots,” he said of his exploits at the third – it was only the second eagle there since 1983. “I hit a great drive down there, really couldn't have hit it any straighter where I was aiming, and then had 110 yards.
“Having a wedge in our hand, we're trying to hit it close and obviously give ourselves a look at birdie. It was going right at it, landed just past the hole, came back, and from my angle knew it was going right down the stick so knew it had a chance, and fell right in the back door.”
Because of the threat of thunderstorms the decision has already been taken to bring forward the third round tee-off times on Saturday.
The first start time was 7am local time (noon BST) with the leaders - in threes rather than twos - out at 9am.
