Since this topic was posted on May 19th, I think Patti was referring to Karlen's absence from the show prior to his return in the Leviathan story line.
According to Karlen himself (DS Companion, 25th Anniversary book) he had moved his family to California and was lured back to New York by Dan Curtis after Curtis got the two-picture deal with MGM. Karlen really wanted to do the films.
Interesting Dr. Lang...so, were they just gonna have Willie not be there
(in RT, 1969) with no explanation?
I thought (from IMDB) that he (I guess in CA) was on a different soap opera
Patti