12/27/2012 10:01 am ET

Jason Ritter In 'Parenthood' Season 4: Jason Katims Talks Mark, Sarah And Hank

Have we officially seen the last of Jason Ritter on "Parenthood"? Not according to series creator Jason Katims.

Not only has he promised that Mark (Ritter) will return, but he hinted that his relationship with Sarah (Lauren Graham) may not be entirely over ... even after Sarah and her boss Hank (Ray Romano) slept together in the show's Christmas episode.

“We certainly have set up that there’s a chemistry between the [Sarah and Hank] that they both are aware of, but this does not mean that Sarah has put an end to the relationship with her and Mark, either,” Katims told TVLine. “We have not seen the last of Mark ... there’s still more to be figured out. It’s not just over.”

Ritter also hinted at his return to the NBC drama via twitter last week.

In October, Graham told The Huffington Post about Ritter's reaction to Romano's guest spot. "Ritter sent me a text that was like, 'Everybody doesn't really love Raymond, right?' There have been lots of plays on words."

"Parenthood" returns to NBC on Tues., Jan. 1 at 10 p.m. ET on NBC.

Do you think Sarah and Mark will get back together? Sound off in the comments.