Tim Herron holds a one-stroke lead at the Pebble Beach Pro-Am but he is under pressure from Australian youngster Jason Day, who is just two shots off the pace at the Californian tournament. A frustrated Herron, though, was forced to change his putters at the start of his round on Friday (US time), but the move eventually worked for the American as he posted a two-under 70 at Poppy Hills to climb atop the leaderboard with a score of seven-under overall. However, with the greens at the three venues where the tournament is being played, known for their trickiness, Herron is more than aware that any player who makes the cut after the third round on Saturday is in with a chance of winning. After day two, the American is just one stroke ahead of an American quartet consisting of Robert Floyd, Michael Allen and J.B. Holmes, who all scored two-under 70s on Friday, while Nicholas Thompson moved into the tie for second via a three-under 69 at the Pebble Beach course. Twenty-year-old Australian Day, the youngest player on the PGA Tour this year, followed up his first round 69 with a two-under 70 on day two of the tournament, starting brilliantly with three birdies on the front nine before carding two bogeys and a birdie coming home to be in a six-way tie at five-under overall. His countryman Matthew Goggin is a further two strokes adrift of Day after having an up-and-down day on the course. Goggin carded three bogeys in his round but more than made up for it with five birdies, including two on the 16th and 18th holes, to climb up the leaderboard and be in range of taking the lead. Goggin is one stroke ahead of compatriot Steve Allan, who is at two-under overall after a posting a one-under 71 on Friday alongside Matthew Jones (72) and Andrew Buckle (73). Further back in the field, New Zealander Grant Waite (71) is on even par overall alongside Australian Gavin Coles (70), with both players two strokes ahead of Greg Norman who came back from hitting a 76 on Thursday, by producing an impressive two-under-70 on day two that gives the &aposShark&apos the chance to make his first US PGA cut since 2006. Norman is alongside compatriot Michael Sim (74) and two strokes ahead of David Lutterus (76), with Steve Elkington (72) on six-over and former European Tour player Brett Rumford (74) eight-over for the tournament. Mark Hensby (78) is on ten-over, one stroke ahead of Kiwi pro Phil Tataurangi (79) and his compatriot Tim Wilkinson (82), who had a shocker on Friday after carding a somewhat respectable 74 in the first round.