Carroll is brutally honest about Marshall. He's here to compete, but there are no guarantees. Carroll has had successful big WRs throughout his coaching career, but it's been hard to find a guy like that. They keep trying, and bringing Marshall in is part of that. You're either competing or you're not.
I thought this was probably his most interesting press conference of the year, particularly his descriptions of what new coordinators Ken Norton, Jr. and Brian Schottenheimer add to this team.