Two months ago, Castle star Nathan Fillion‘s no-show for work on a Friday, which we reported about, drew a lot of attention. It led to a production shutdown for the day and came in the midst of a contract dispute between the actor and Castle producer ABC Studios over Fillion’s request for a four-day Monday-Thursday workweek on the show, currently in production on its sixth season. There had been no major incidents since, with filming moving on as planned. But when today, also a Friday, Fillion called in sick, the news stirred a lot of speculation around the set about a possible new work schedule dust-up. According to sources close to the production, Fillion had a legitimate reason to skip work today — a sore back he is seeing a chiropractor for. His back problems are reportedly chronic, and he gets medical attention when they are aggravated. The production had enough of a heads-up to schedule some filming around Fillion for the day, a source said. Insiders stress that the schedule issues between Fillion and ABC have been resolved and he has worked multiple Fridays in the past two months. Fillion is expected to report back to work Monday.