Ever since Supergirl first aired, there has been a number of tips of the hat honoring the history of both Supergirl and her cousin Superman on the show. One of the main ways it has occurred has been through casting. Both the previous actresses who have played Supergirl in live action film and television have played reoccurring roles, Helen Slater from the movie Supergirl as Eliza Danvers and Laura Vandervoort from Smallville as Indigo. Recent casting announcements have included Teri Hatcher and Kevin Sorbo. Hatcher played Lois Lane on Lois and Clark: The New Adventures of Superman and Sorbo was originally cast as Superman - before he was replaced by Dean Cain.
Cain was also cast on Supergirl, he's played Jeremiah Danvers since the first episode. His presence in season 1 was confined to flashbacks, as the character had apparently died sometime between Kara's arrival on Earth and the present day. It was near the end of the first season that the characters learned the truth - Danvers was not dead, he was captured by Cadmus. He's been seen in the present only once, when he helped Mon-El and Kara escape Cadmus.
In the synopsis for the upcoming episode, 'Homecoming', the return of Jeremiah Danvers has been promised. Though as should be expected, things will probably not be very simple:
DEAN CAIN RETURNS – When Jeremiah Danvers (guest star Dean Cain) is rescued from Cadmus, Alex (Chyler Leigh) and Kara (Melissa Benoist) are thrilled to have their father back. The Danvers arrange a family dinner to celebrate but things go awry when a suspicious Mon-El (Chris Wood) starts to question Jeremiah about his sudden return. Larry Teng directed the episode written by Caitlin Parrish & Derek Simon.
Danvers has been a prisoner of Cadmus for a very long time, over a decade. As evidenced by the experiments they performed on Hank Henshaw/Cyborg Superman as well as Metallo, it is clear that Cadmus has no issues with experimentation on human beings in order to achieve their goals. So it would seem reasonable for Mon-El to have some doubts.
It seems like trust is an unofficial theme of the second season. All of Kara's friends keep telling her not to trust Lena Luthor, even though Lena has repeatedly shown herself to be a friend. James, Winn, and Alex all kept the truth about James being Guardian a secret from Kara, and since finding out Kara's been struggling to trust James' abilities as a vigilante. It seems as though 'Homecoming' will continue that trend, with Mon-El and Jeremiah as the characters whose trust is in question.
Supergirl continues on the CW with 'Luthors' on Monday, February 13 at 8 pm. 'Homecoming' will air on February 27.