Yeah Cummings is an ILB. Pace, Thomas and Murrell are our only OLBs right now, which makes me think Gholston's injury has to be legit. Edit: Apparently Cummings played DE in college though, so I wouldn't be surprised if he was added for OLB depth.
We also have Westerman as a ILB/OLB Hybrid... I think Cummings will battle it out with Fowler on being active on game day... whoever is more useful to ST plays.
Plus he used to play DE in college so he has experience as a pass rusher. Most likely he'll contribute in special teams, yet another role in which Gholston absolutely sucked.