It may depend on the timeline. If essentially nothing happens legally by the start of the season, I would say 4 games. I don't know how long it takes to push a misdemeanor through court, but if he does get convicted prior or during the season, you may be looking at jail time with a suspension afterward. Losing half the season wouldn't surprise me. At this point, these guys have been sent the message - to give the NFL a black eye (literally) these days, there is just no excuse. Penalties for stupid "thug" activity like this could get harsher, because for all the PED and DUI crackdowns, it is really the "thug" image the NFL is trying desperately to leave behind and has no tolerance for.
I'm not sure if he has any prior offenses with the NFL (other than playing like crap in Chicago), but did we mention he plays for the Bengals?