Given how easily Kyuubi Naruto was nerfed by Oro, I don't think that Itachi was talking about anyone besides Jiraiya.

Naruto ... no he's tough, but not fast/smart enough to face Itachi
Kyuubi Naruto .. tougher, but can be dealt with (Oro/Kimi)
Sasuke .. lmao no way
Jiraiya .. bingo [img]i/expressions/face-icon-small-smile.gif[/img]