According to TVLine, soap vets Nancy Lee Grahn and Jack Wagner are headed to the ABC drama with Grahn getting involved in a squabble with Beckett (Stana Katic) and Wagner guest starring as a pro golfer whose wife is found dead.
Season 5 of "Castle" will return to ABC on January 7.
In other casting news...
Robbie Jones is headed to "90210." The "One Tree Hill" vet will recur as Jordan Welland, an intelligent publisher who becomes interested in Naomi (AnnaLyne McCord) on the CW series. [TVLine]
Sean Hayes is looking to be a permanent NBC fixture. The "Will & Grace" actor is reportedly producing in an NBC comedy centering on a dad and his 14-year-old daughter who recently moved in with him. [Vulture]
Terry Kinney is "Elementary"-bound. The "Oz" vet will appear in the CBS series' Superbowl episode as as "an unpredictable criminal who causes chaos in New York." [TVLine]
Chloe Bennett has joined the "S.H.I.E.L.D." cast. Bennett has joined Joss Whedon's pilot as Skye, a superhero obsessed, confident woman. [THR]