TAMPA, Fla. — Each spring there's a name or two that pops up, turning heads in the Yankees' front office.

Who will it be this time?

Well, the Yankees have a bunch of non-roster invitees — 25, actually. And while the Yankees' brass is one of the league's most prepared, even they could be surprised by what they see out certain players.

While it's too soon to make any real, concrete calls about who will end up on the 25-man roster, a few non-roster invitees have stood out, and could make it difficult for decision-makers when Opening Day rolls around.

Here are five of them.