PJ, Neill and Hetherington almost always start. Devine is probably first choice too, but regularly misses out through injury.
Big Sammon has started on the bench for several weeks now; possibility he may start this one IMO, with Wales back to Kilmarnock as he gives us more physical presence than Ally Roy and that may be the way Andy Graham chooses to go.
In fact I'm curious to see whether Andy sticks with his usual line up or tweaks things specifically for Motherwell. He may also see the game as an opportunity to give guys returning from injury some game time (e.g, Robbo, LD).