England's Paul Casey (-10) remains just one shot off American leader Kevin Chappell (-11) after the second round of the Deutsche Bank Championship in Boston.
Casey, whose decision not to renew his European Tour membership made him ineligible for the Ryder Cup, made seven birdies over the last 10 holes to card 66 and stick just one point off the lead.
World number one Jason Day has joined Luke Donald and nine others on one-under, while Rory McIlroy hit seven birdies to lie four-under in a four-under-par 67.
American Jimmy Walker is also on 10-under at the halfway stage of the competition, while Justin Rose is on seven-under.
The cut, meanwhile, which came at one-under, claimed the likes of Bubba Watson, Phil Mickelson, Martin Laird and Graeme McDowell.
