They know his reputation. They also know what he can do on the field.
Jackson won't work out with his new team until next week, a team source said. He told coaches before signing that he had a vacation scheduled for this week based on Eagles players not needing to report until April 21.
Philadelphia cut Jackson on March 28.
While some of his new teammates weighed in on the move last week -- quarterback Robert Griffin III and cornerback DeAngelo Hall both recruited Jackson -- two more provided their support Monday, starting with nose tackle Barry Cofield, a captain last season.
"A guy I absolutely hated playing against for eight years and a guy that hurt my teams countless times," Cofield said. "So I was very excited getting him."
Left tackle Trent Williams, a captain the past two seasons, said he got to know Jackson at the Pro Bowl. The minute Williams said he heard about Jackson being cut, he texted the receiver to find out whether the Redskins were in the picture.
Clearly, Williams isn't worried that Philadelphia reportedly cut Jackson because of poor work habits.
"Not at all," he said. "We're pretty tight. When he told me they were talking [with the Redskins], I told him we would love to have a player of his caliber and that our team would be willing to embrace him and try to do big things this year.
"A lot of that stuff is he-said, she-said. You got to get to know a guy for yourself. I haven't had any type of bad feelings towards him or any type of bad reads. When I met him he was a great guy, a pretty cool guy. We exchanged numbers and stayed in touch. I don't think he's a bad guy. I don't think his character is bad. He can be a great addition to the team, obviously."
Jackson on Friday gave his version of his controversial release by the Eagles, telling ESPN he is not a gang member and that a report alleging he belongs to a gang was wrong and disrespectful.
The Eagles cut ties with the veteran playmaker after they uncovered information about his off-field connections and activities, a source told ESPN NFL Insider Adam Schefter. Shortly before Jackson was let go by the team, NJ.com published a story reporting that he had alleged gang connections in his native California. Jackson, from Long Beach, refuted the report at the time, and did so again in an interview Friday with ESPN's Stephen A. Smith.
Williams blamed some of the negative talk surrounding Jackson on the heavy attention football receives.
"Picking people apart is a byproduct of that attention," he said. "For a guy that has had the type of impact he has had ... I wouldn't question his practice habits or question him as a player. He's proven himself day in and day out.
"It's human nature, whatever you're doing and all eyes are on you, there's somebody that won't like you. There are always people that say things, so I'm not going to judge him and say he needs to change. I can only go on his body of work and his numbers can stand up with the top receivers in the league."
That production -- 356 career receptions, a 17.2 yards-per-catch average -- is what the Redskins want. But taking on a player with Jackson's reported red flags can be a test for leadership.
Cofield, though, said leadership is not just about fiery speeches. It's about everyday behavior. He said former linebacker London Fletcher was respected for his approach -- it wasn't about any pregame emotional talks.
"Leading by example is one of the biggest things you can do," he said. "If all our older guys, more experienced guys, naturally look up to carrying themselves the right way and being true professionals, that will trickle down and affect the locker room in a positive way.
"You don't need guys running around cracking the whip. You just have to have old guys, the vets we trust, doing things the right way. Play well and prepare properly and be true professionals. Then all that stuff will take care of itself."