Up until now we'd observed that production on 'Castle' season 6 had gone swimmingly, recently casting 'House' star Lisa Edelstein for a recurring role as photos from the set emerged. Now however, 'Castle' season 6 seems to have hit an unusual snag, as normally affable star Nathan Fillion reportedly refused to show up for work this past week, citing a conflict with producers at ABC studios.

Deadline first reported the news, clarifying that Fillion's push for a four-day work week came to a standstill with the 'Castle' bosses, and Fillion's absence from the set this past Friday was "his way of sending a message." Representatives for ABC insist however, that the show continues to shoot this week, and Fillion has been on set.

As TVLine notes however Fillion's usually-active Twitter account made relatively few posts on the Friday in which he supposedly refused to come to set, contrasted with the previous day's photos of he and Lisa Edelstein, among others. Thankfully for 'Castle' fans, barring any further issues with Fillion or his contract, the show has resumed production on the sixth season and will premiere on Monday, September 23.

'Castle' will be absent for the second year in a row at Comic-Con 2013, but in the meantime, what say you? Could Fillion's issues with producers delay the show any further?