Paul Casey
Casey co-leads at the half-way stage in Wisconsin. Getty Images

English pair Paul Casey and Tommy Fleetwood are among four players with a share a lead of the US Open at the half way stage at Erin Hills. Joined by Americans Brian Harman and Brooks Koepka on seven-under, the leaderboard for the second major championship of the year has concertinaed up meaning any of the 68 players to have made the cut for the weekend have a chance of scooping the title.

That group does not include defending champion Dustin Johnson, who fell away in the second half of his round, while Rory McIlroy and John Rahm will both have a watching brief during the concluding rounds in Wisconsin. World number one Johnson becomes the ninth player to miss the cut having won the USGA's blue ribbon event 12 months previous.

Overnight leader Rickie Fowler looked set to retain his place at the top of the leaderboard but broke his 28-hole streak without dropping a shot with three bogeys in as many holes to derail his campaign. The 2014 runner-up is just one-shot behind alongside Jamie Lovemark and JB Holmes.

"You'd definitely take it, said Fleetwood, whose previous best finish at the US Open is tied for 27th. "Today I started off a bit ropey. Putting kept me in it early on and then I started hitting it great from seven onwards. I felt really comfortable and I was enjoying being out there. When it is the US Open and you're leading it is a different type of pressure because it is new so I'll see how that goes tomorrow."

Tommy Fleetwood
Fleetwood made a second round 70 to jump to the top of the leaderboard. Getty Images

The round of the day came from Japan's Hideki Matsuyama, who ended at five-under after a round of 65 propelled him into contention to win his first major title. Amateur Cameron Champ is on an identical score after another under-par round for the 22-year-old, while Si Woo Kim, Xander Schauffele and Brandt Snedeker are also two shots back and well placed.

The 2011 champion McIlroy shot a second round 71 but his horror opening score of five-over on day one means his uncertain season continues as he missed the one-over cut line; the joint-highest in US Open history. Fellow-countryman Graeme McDowell follows him out of the tournament, joined by the likes of Jason Dufner, Jason Day and Danny Willett - who withdrew due to the recurrence of a back injury.

"I've been very light on competitive rounds," McIlroy said. "I think at this point in time I just need to play. And I feel, even though it's very disappointing to not be here on the weekend, these last two rounds will serve me well going into the summer. Yesterday, coming off an injury, I was a little anxious going out there. I got off to a good start but it sort of caught up with me as the round went on. I think the more rounds I can play, I'm hopefully going to get rid of all that stuff and hopefully strip it down to what you saw the last six holes."

In all, eight of the world's top 12 will the absent from the shootout for the title, including each of the top three for the first time since the world rankings were introduced in 1986. Two shots might separate the top 12 players - with just eight shots spread across the entire field - but the leaderboard is devoid of high-profile players and marquee names.