"Our relationship at the outset was a little weird, a little shaky," he said. "I didn't realize how intense he was. We bumped heads a little bit but then I saw where he's coming from and he understood where I was coming from, we ironed the wrinkles out."
Henderson said he knew Singletary was intense before he joined the Vikings because he'd seen clips of him as a head coach: "But it's different when you're face to face with him and he's looking at you with those ice-cold eyes. You say 'okay how upset is he really right now or is this just his normal way about things?' We eventually figured it out."
Linebacker Chad Greenway is among those anxious to play a game Friday against a real opponent. He also said fans should keep an eye out for Marvin Mitchell who will start at weakside linebacker.
"Everyone is having a great camp.," he said. "But Marvin Mitchell has been a leader and I think he's going to do well."
Sullivan values experience
Center John Sullivan has been a member of the Vikings offensive line for six years and has matured into the leader of the group. This summer is the first time during his tenure the Vikings have had all their starters back and healthy from the previous season.
"In the 2010 and 2011 seasons we had everyone return, but injuries set us back," he said. "This year we have all five guys back and we're healthy."
Joining Sullivan on the line are Matt Kalil and Charlie Johnson on the left side and Brandon Fusco and Phil Loadholt on the right side. Like Greenway and Frazier, Sullivan is looking forward to Friday's game.