Johnny Galecki talks about Roseanne and TBBT
http://tvline.com/2018/01/06/big-bang-theory-ending-final-season-12-johnny-galecki/
Galecki said that scheduling played a part in his Roseanne encore being so brief. But the fact that he revisited his role on a rival network’s sitcom at all is not to be taken lightly.
When TVLine asked Galecki if the negotiations for him to be lent out to Roseanne were delicate, he nodded, “‘Delicate’ is a good word for it.
“It was probably most unconformable only to me,” he continued, “because obviously Big Bang is my home and my family. But I probably wouldn’t have been on Big Bang if it hadn’t been for Roseanne. So there were the politics to be considerate about, but everyone was very supportive.”
And if Roseanne in success is renewed for next season, he hopes to play David a bit more. “If they come back next year to do another eight or nine [episodes], I would love to do more than one [episode].