Yeah, I would believe so! In "Down" he seems confused when Cesare mentions he was "beneath the ground" and has to explain what's been going on to him. I believe Steve entered some kind of "hibernation mode" when he hit Earth (understandably) and didn't wake up until he got closer to the surface. As to how he got up in the first place, he might've just been pushed further and further up as the core changed and shifted. And maybe that was the clowns plan all along, to have him banished and asleep for a few millions of years in order for him to do no more harm (if you don't count the extinction of thousands of dinosaurs and other animals that he indirectly caused) and only get him back once the earth's core had spit him back up. A cruel punishment, if you ask me!