The MLS sites are a bit iffy on player classifications. For instance, they list Kuffour as a TI/Disc, but he's actually signed to a developmental contract and counts as a roster protected player. You'd think he'd count towards the senior squad judging from the MLSNet classifaction. Here's a thought about your question. Perhaps Roberts was put on IR, but Colorado didn't really get any roster relief because they still had open spots on their roster. (That would mean the 7/2 press release is wrong, or at least misleading.) As I understand it you can only get roster relief when you've filled your whole roster. If Colorado still had open spots on their roster then they'd need a way to acquire a player to replace Roberts, and for that a discovery would work. That said, I haven't followed Colorado's roster at all. But it's a theory ... Maybe it fits. Did Colorado have open spots on the roster at that time?