They were once close but with the present situation, many are watching each move by "The Vampire Diaries" stars Nina Dobrev and Ian Somerhalder. There are notions that the upcoming episodes are dependant on how well the former couple would set aside their differences.
Given the rumors, there are no affirmations that "The Vampire Diaries" would bring Elena on board. If ever it materializes, it would mean that Nina Dobrev would return to the spotlight alongside Ian Somerhalder. It is irrefutable that their names are always tangled in more ways than one. There are presumptions that both would find it difficult to work in the episodes for "The Vampire Diaries" given their romantic history. However, it does not imply that it would never occur.
According to Hofmag, Nina might not appear in the next episode, owing it to Ian's presence. The report mentioned that Nina Dobrev might still decline and would not grace "The Vampire Diaries" with her presence at all. On a different note, Nina Dobrev's presence in "The Originals" would surely bring unprecedented scenes since Klaus and his daughter are fated to render an appearance in the next scene, as previously reported by GameNGuide.
However, there also notions that Nina would rather appear in the "The Originals" rather than play her part as Elena in "The Vampire Diaries." There are still too many left undone for the series but until Nina confirms her return, everything should still be taken with a grain of salt in mind.