This is the effect of questionable character.
Not only do you have a reputation of being "less than professional" since his college days, but gets into an altercation on the eve of the most $$$ lucrative day of his life. This could've cost $100,000 to $200K in bonus, plus a reduction in guaranteed salary if he signs a long-term contract.
Here's a list of good character traits: https://graceonlinelibrary.org/home-family/christian-parenting/49-godly-character-qualities/ 
According to ESPN:
LSU running back Derrius Guice, who slipped to the Washington Redskins as the 59th pick in the draft Friday night, disputed the notion that NFL teams had concerns about his off-field conduct.
The 5-foot-11, 224-pound back denied reports of being involved in an altercation during his pre-draft visit with the Philadelphia Eagles and said he doesn't know about an NFL Network report that there might be another story coming out that could be "embarrassing" to him and the Redskins organization.