On this Sunday's episode of Brothers & Sisters, Tommy returns.

But that on-screen drama - which you can preview right now - is actually nothing compared to the action taking place away from the set of this ABC hit.

As first reported by Entertainment Weekly, an ABC spokesperson has confirmed that Monica Breen and Alison Schapker are out as showrunners. Veteran writer David Marshall Grant will take over lead producing duties.

There's no way to predict how this will affect any storyline, but a network rep says Breen and Schapker will keep their executive producer titles, but are now “concentrating more on development.”

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.