I'm not in Buffalo.
But I thought I'd pass on the official depth chart at this point.
http://www.ourlads.com/secure/depthchart.cfm?index1=buf
Our Lads updates the depth charts throughout the week as the teams release them. This chart has Jackson pretty deep. Although there is no rule, a team will usually keep eight wideouts - with the last two on the depth chart being kick returners/special teams guys.
Interestingly, James Jett (the former Oakland player) is listed four deep - looks like he's just trying to make the Bills. And if he has some speed still, he just may. And Charles Johnson, a nine year vet, is listed five deep. This is shaping up to be a battle of the vets versus the rooks, it will be interesting to see which way the Bills go.
Hope your guy makes it. He'll need to play better than the others on special teams.
Hope that helped.