( Note to readers: Some spoilers below.) First, the rumors. There have been reports that Mark Harmon, who has played Leroy Jethro Gibbs on "NCIS" since the series debuted in 2003, could either leave the show or shift to a part-time role next season. Harmon's contract is expiring after the current season, the 18th for "NCIS," and so that's why there is speculation about his future. If that wasn't enough, "Watchdog" adds more fuel to the fire about what's going on with Harmon and his Gibbs character. Episode summary What appeared to be the main storyline was the pursuit of a dogfighting ringleader, Luke Stana (played by Max Adler). As the episode progresses, the evidence mounts against Stana â there are steroids found in his trailer, which suggests that he's been giving the drugs to the dogs to boost their performance. There are dead dogs found in a pond near his trailer. Near the end of the episode, the NCIS team finds Stana in a barn full of dogs. The team gets their man (again).Â