I was watching a video on iPhone of Baez tagging a runner trying to steal second during a Cub-Cardinal game now being played. The helmet flew off the runner’s head and Baez tagged that first before actually tagging the runner. The runner was called Out and he might have been out when Baez tagged his body. But suppose that tag was late. Would the runner still be out if just the helmet (which was detached) was tagged in time?
I guess this should be moved to the Game Room.
I doubt that tagging a helmet does anything. They fly off a lot and I’ve never seen a runner go back and pick one up until timeout was called.
Helmets often fly off but the fielder does not usually tag the helmet after it has come off.
From the MLB Rulebook:
So no, a helmet that fell off can’t be tagged.
Nah, you can tag it all you want. It just won’t get the guy out. 
Moderator Action
Off to the Game Room (from GQ).
What if it still has the head in it, but detached from the body?
Then the runner is permanently out.
Oh yeah? What if it’s not his head?
He’s out. The rule is clear.
I love that my favourite sport makes it quite unambiguous that a decapitated player is still out if you tag his severed head.
What if his feet are touching a base with his decapitated head lying somewhere else? Is he still out? I’d really like a cite on this rule.
He’s safe, going by the letter of the rule, if a part of the dead body gets to the base (and presumably maintains contact with it) before the head is tagged.
Of course this raises the question as to how the runner’s head came off; for the above interpretations to be correct, we must assume the runner was NOT beheaded by a fielder committing an act of obstruction.
EXAMPLE A: Smith hits the ball into the gap and attempts to stretch the hit into a double. While advancing to second, a sword accidentally dropped from a passing helicopter beheads Smith. Smith’s body collapses towards second base while his head merrily skips along next to it. If shortstop Jones tags the head before the body gets to the base, Smith is out.
EXAMPLE B: Same situation, except the second baseman Williams pulls a sword from his uniform and beheads Smith. Smith’s body collapses towards second and shortstop Jones tags his rolling head. Williams’s actions constitute obstruction on the affectef runner and the play, like Smith himself, is dead at the moment of decapitation. (Rule 6.01(h)(I)). Smith is awarded second base even if his body does not reach it; any other runners are awarded a base if they were advancing to it when Smith was murdered. Smith may them be replaced with a living player prior to the resumption of play.
Williams argues “I was tagging him. The sword hand is my glove hand, and the ball is still in the web! And I was well out of the base path; I tagged (and decapitated) Smith with a sidearm stroke from out here in the outfield side of the bag! No way that’s obstruction!”
This is a very good case of why a player substituted out is ineligible to return to play. :o
Actually just the player is dead. Obstruction does not end the play. The play continues until the ball is dead and the umpires can then award players the base to which they think they would have advanced. So Smith might be awarded third base as well. If obstruction ended a play, and runners were awarded the base to which they were advancing, third basemen would tackle runners coming from second on singles to prevent them from scoring.