The three game ban may seem hefty but we all knew the suspension was looming from 2014's incident with LeGarrette Blount. Bell will obviously be appealing the suspension but winning an appeal in the NFL is a rarity so expect the three game tag to stick.
The Steelers signed DeAngelo Williams this off-season in a much needed backup role so he will likely be doing fill-in work while Bell is unable to play. Williams has always been a talented player but was unfortunately stuck in a cluttered backfield while a member of the Carolina Panthers. The news of Bell's suspension makes Williams' role clear; he's the backup who will almost certainly take the starter's place.
Although the suspension/appeal process carries more weight in real life football than it does in fantasy, the three game ban obviously impacts Bell's draft status. Prior to the news of the suspension, Bell was pretty much the consensus number one player heading into the 2015 fantasy season. Despite only being able to draft Bell for 13 games, he should still be treated as a highly valuable first round pick. He shouldn't fall any lower than five or six even with the suspension. In looking at the rest of the first round, you really only have three "safe" picks in Jamaal Charles, Eddie Lacy, and Marshawn Lynch. Rank those guys anyway you want but Bell shouldn't go much later than them.
Beyond that, there is risk involved with every other back in the first round. Adrian Peterson hasn't played in a year, Arian Foster is an aging back who is notoriously banged up, and DeMarco Murray is on a new team with health concerns of his own. I would be perfectly comfortable taking Bell at four or five and just going out of my way to take Williams early.
I know this may seem early for hardcore fantasy analysis with it being April and all but I'm sure there are plenty of fantasy obsessors out there, myself included, that saw this news whose wheels immediately starting spinning. If you're in a keeper/dynasty league, do yourself a favor and add Williams ASAP. We'll re-evaluate this situation once Bell's appeal process is handled as well as once we get into fully analyzing draft strategy for the upcoming season. But for now, relax, the number one running back in fantasy is at worst a mid-first rounder.