First Rodriguez, Looks good up here but doesn't have the speed required for the NFL or the route running ability. Uses his size mainly to go after the ball and I've seen him get hemmed up good against some of the corners here in Winnipeg.
Dorsey, has good speed but would be nothing more than a return man in the NFL he was cut by the Redskins at the end of training camp. He's just to small to be a quality back, but he's a shifty runner but would get knocked ove by arm tackles.
Mallett, is probably one of the better backs but isn't the best pure running back even in the CFL tho he does lead the league in rushing at the moment. He runs hard but with the Size difference in the NFL i think he would get owned at the line of scrimmage plus he doesn't run terribly fast i can think of atlest 3 backs that are better in the CFL.
Parker, Is a corner in the CFL not a safety. He doesn't have the speed to make plays in the NFL and has looked average at best in plenty of games here in the CFL i can remember Stegall owning him multiple times. As well as other WR up here. He is a bit of a ballhawk at times but againt much faster and larger WR he would have no chance.
Just for reference the all time best WR in CFL history couldn't make it in the NFL Milt Steggall look up his records.
There are a few CFL player who could make it but they are few and far between. Cameron Wake is one who looks good in the NFL for the dolphins, up here he Played D-Line down there he is a LB that should give you an idea of the size difference between the 2 leagues.
Garcia and Flutie both had success as well but The Best QB in the CFL right now Calvillo for the Alouettes can't even get a sniff in the NFL and he passes for 4000+yds every single year like clockwork. It's a different league up here and tho i love it the Talent is not even close. Hell i can't even think of a WR from the CFL who has managed to stick as an NFL WR.
Just some insight from a fan of the CFL for the last 25 years.