But for all the times we've seen him (with the exception of flashbacks and when he ran out of chakra) he's had it up, whether he needed to or not. who's to say Tobi isn't the same way? Besides, he's obviously older than Itachi, and Itachi's chakra was subpar anyways, so it's logical to assume that he would probably have more control over how long he can keep his sharingan out. Now i'm not saying that he DIDN'T have a transplant. What i'm saying is that it's just as like that he didn't as much as did. It irks me to see ppl ignore certain facts and try to say that their theory is absolutely correct when there is evidence or proof otherwise. People like to forget that Tobi used to have 2 sharingans, too, when he fought Konan. People like to forget that Tobi was a full grown adult when he took on the 4th Hokage (Kakashi was still be a teen). People like to dismiss the fact that Obito was a pacifist with no motives against the leaf village (can you tell where i'm heading with this, Tobi=Obito conspiratists?) Not to mention that he had just awoken his sharingan moments before getting crushed, which would completely rule out his Mangekyo activating. Lastly, the fact that Obito is Tobi with an extra "o" is a complete coincidence. It doesn't spell that way in Japanese, and Tobi means "kite" which is meant to relate to a proverb with Sasuke's team, Taka [Hawk].