Johnson is a 30 yr old 4-3 player. He is a first and second down DE and a passing down and distance DT. Being able to play both may be his biggest asset. I see Kelsay only as 4-3 DE and can't imagine him as an OLB again. Dwan Edwards is a 30 year old 3-4 DE and should be traded for a 7th round pick, a blocking sled, or released. Arrington, well who knows what he is. He was drafted as a 3-4 pass rushing DE. Then he was switched to a 3-4 OLB and lastly back to a 4-3 DE or even at times DT. I see him as the backup to Mario at DE.
My DL going into camp: Mario Williams, Kyle Williams, Dareus, Anderson, Arrington, Troupe, Heard, Johnson, Kelsay and two undrafted FA's for trainging camp bodies. I think they keep 8 DL. Heard or Johnson will fight for the last spot and I suspect his age and the cap space provided by letting Johnson go will be the determining factors.