Gamasutra is reporting that two key senior members have left the Bioshock Infinite studio, which is causing some concern among gamers on the future of the next title in the Bioshock series.

Tim Gerritsen, director of product development, and art director Nate Wells have both announced their departure. Wells was a 13 year veteran of the studio, whose distinctive style was heralded in the original Bioshock.

While such departures are normal for studios when a game is approaching a more polished state and the teams are thinned down, it does raise concerns on how well the development is going for Bioshock Infinite. With the previous release date having been set for October 16th this year, Irrational since then has pushed the date forward to an early release next year, citing that "Bioshock Infinite is a very big game, and we’re doing things that no one has ever done in a first-person shooter".

Ken Levine, founding member of Irrational Games, did post up on his Twitter that previous Bioshock 1 art director Scott Sinclair will be taking up the vacant position, at least calming some fans about the recent loses. However with such departures comes scepticism that Bioshock Infinite may push its release date back even more, however no confirmations have been made yet.

Bioshock Infinite is set to be released for Xbox 360, PC and PlayStation 3 on February 26th, 2013.