Graeme McDowell has continued his steady play in the US Open with three more pars to stay at one under after five holes, where he was joined by Poulter, who birdied his opener at the testing par-four 10th and was still at one under after four holes.
Englishman, Lee Westwood, was also making considerable inroads, joining his Ryder Cup team-mates at one under thanks to three birdies in a row to open, starting from the 10th.
Then McDowell dropped a shot, bogeying the sixth hole to drop to level par, while Players champion Henrik Stenson was one under for his second round after four holes, two over for the week.
Woods parred his first three holes before claiming his first birdie of the day at the 13th hole, his fourth. Playing partner Harrington had birdied his second hole of the day at the par-four 11th to move to five over par after four holes while Masters champion Angel Cabrera – the third member of the majors champions’ group – dropped to the same mark with a bogey at the fourth.
Harrington, though, was gaining momentum in his second round, as temperatures cooled and the skies over Long Island darkened, adding another birdie at the fifth to move to four over.
Luke Donald was static at five over after five holes, having opened with a bogey, followed by a birdie at the second and another bogey at the fifth.
Laird finished at five over for the week after a one-over 71 but Casey, a three-time winner this year, carded bogeys at the second and fourth to slip to seven over.