Fans Are Afraid 'NCIS: Los Angeles' Won't Last Without Callen — Is Chris O'Donnell Leaving?

Viewers of NCIS: Los Angeles are getting antsy as the end of Season 13 approaches. They're nervous not only because it's the end of the season, but because rumors have begun to circulate that original cast member Chris O'Donnell might be leaving the series. Is Callen really leaving NCIS: LA? Would there even be a show without him?

It's not an unnatural question to ask. O'Donnell has been playing Callen for longer than most entire TV shows stay on the air. Stars of long-running shows often develop a desire to move on and do other things. Primetime viewers saw exactly that this season with Jesse Spencer on the NBC hit Chicago Fire.

So, is Chris O'Donnell thinking about moving on? Here's everything to know about the rumors regarding his (and Callen's future) with the NCIS franchise.

The latest NCIS: LA episode, "Live Free or Die Standing," had Callen and his partner Sam Hanna in the thick of the action, like usual. But even though the duo are always getting into trouble, there's no indication that the series plans to kill off Callen or otherwise hand him his walking papers.

Since Callen and Sam's partnership is the foundation of the show, it's unlikely that CBS would have renewed NCIS: Los Angeles if O'Donnell wasn't involved.

Both he and LL Cool J (who plays Sam) are also executive producing CBS's new reality competition series Come Dance With Me, so they're obviously wanting to stay in business with the network.

O'Donnell hasn't said anything publicly about wanting to leave or wanting more for Callen as a character, even though Linda Hunt's Hetty being gone has meant the show adding more drama to Callen and Hetty's relationship.

So, is Callen leaving NCIS: LA? Not unless Chris O'Donnell is as good at keeping secrets as his TV alter ego, because he's shown that he's committed to the character and the show for the long haul.

There are only a few episodes left in Season 13 of NCIS: L.A., but there are still big things ahead for Callen before the season ends.

The official synopsis for the May 8 episode, titled "Work & Family," says that Callen "wants to take the next step" with his love interest Anna Kolcheck (played by Bar Paly). That's another vote of confidence toward him staying. It's unlikely the show has him reach that romantic milestone only to get rid of him shortly thereafter.

Plus, the ongoing story involving Sam and his father continues, and Callen will obviously want to be there for his longtime partner and best friend if Sam needs his support. Their friendship has carried them through just about everything that could happen on a procedural, so Callen wouldn't bail while Sam is going through family drama.

"Work & Family" is also the 300th episode of NCIS: Los Angeles, so there will no doubt be some callbacks and other surprises hidden in the hour to mark the occasion. Fans will want to make sure they tune in for the episode, which is one of just three remaining this season.

NCIS: LA airs on Sundays at 9 p.m. EST on CBS.