In his second NFL season, Henderson took over at inside linebacker when 11-year veteran Greg Biekert retired after last season.
Off the field, Henderson was arrested twice before the 2004 season, for drunken driving and for his alleged involvement in a nightclub fight. He was found guilty of the former, and the latter charge was dropped.
"It's not just embarrassing to me," said Henderson, a graduate of Aberdeen High. "It's embarrassing to my family, my fans, the people at home."
"I just told him not to worry," said his brother, Erin Henderson, a former Sun football co-Player of the Year at Aberdeen who was a redshirted freshman this past season at Maryland.
"I mentioned that he needs to slow down. It's hard when you're put in that situation with all the money coming at you. It's a whole other level."
E.J. Henderson said regardless of his off-field behavior, he is focused on his job, which is playing football.
"He's had ups and downs this year on the field," said Vikings assistant linebacker coach Pete Bercich. "As a linebacker, the thing you have to remind yourself is that you are the quarterback of the defense.
"He came into the season as the starting linebacker without ever starting an [NFL] football game before."
Henderson missed two games this season after spraining his knee against the Chicago Bears on Sept. 26.
"He's held up well thus far with the sprained knee. The thing about E.J. is that he'll play with painful injuries," said Bercich. "My hat's off to him."
"I had a couple rocky games, and now I'm at the point where I'm at right now," said Henderson, who had 94 tackles this season. "I'm just focused on studying hard and coming out every weekend and getting the defense lined up and coming out and making plays."
Bercich says Henderson is showing signs of improvement but still has a lot to learn.
"With a young guy, you are constantly working on his awareness, making sure he knows where to fit in the defense," Bercich said.
"He's spent a considerable amount of time learning the system. He has struggled with that, but I know he's also getting better with that."
His struggles off the field were from the two arrests.
On April 10, he was charged with driving under the influence on Interstate 95 in Harford County and was arrested again on June 6 for allegedly assaulting an unconscious man with three others outside a nightclub in Minnesota.
The charges against Henderson were dropped in the incident in Minnesota, but the Harford County District Court found him guilty of driving under the influence.
He was given a two-year probation before judgment, paid $1,020 in fines and ordered to attend a shock trauma tour at a Baltimore hospital.
"There are probably some people that heard the news or saw what happened and probably looked at me like I was the worst person in the world or just another bad guy, a thug or a criminal," Henderson said.
"But it's not really like that. I mean I made my mistakes granted, but everything isn't always as it appears."
Henderson said he has become more of an adult and has learned from his mistakes and now is ready to put it behind him.
"He's smart enough to learn from what happened," said Bercich. "He wants to be a good football player and will do whatever it takes. I'd be surprised if E.J. has any more run-ins. Only time will tell."