If Dustin Johnson’s putter had been going, he might have left the field in the dust. Instead, the long-bomber scratched out a 4-under 67 in his second round of The Northern Trust at Liberty National Golf Club in Jersey City on Friday, giving him a one-shot edge over a star-studded leaderboard. That includes Jordan Spieth (11-under), Jon Rahm (10-under), Justin Rose (9-under) and Rory McIlroy (9-under). “I felt like I gave myself a lot of chances and very makeable putts all day,” said Johnson, who finished with 27 putts on the day — including an 8-footer on 18 that he made for a birdie, giving him the outright lead going into the weekend of this first leg of the FedEx Cup playoffs. “Felt like I was rolling it good, too. I was burning the edges all day, but hitting my putts with good speed. I did stay patient and I knew I was hitting it good, so I was going to keep giving myself chances.” Johnson won this event two years ago when it was held at Glen Oaks on Long Island, beating Spie...