If there's going to be an abuse of this I think it might most likely be as a way to bring up a fresh reliever to help an overworked bullpen. Teams might be more likely to replace a reliever if they only have to miss 7 days, rather than being sent down for a minimum of 10 days (which is only possible for a player with options) or being placed on the DL for 15 days. I'm for it because a team doesn't have to either go without a player for 15 days or be a man short if the player has a minor injury that would require him to miss around a week. I'd advocate it for any injury, not just restricted to concussions. If there's concern for abuse there could be restrictions set (such as a maximum number of 7-day DL moves per team in a month or a maximum number of times in a season that a single player could be placed on the 7-day DL).