It seems Gerrard knows how to test players to improve them. Alfie, Jack, Barisic, Tav are testament to that. Players that burst a gut to improve and show they're worthy of being there will get their chance, as Halliday mentioned last week.
After hearing what Windass and Lafferry have said though it does seem Gerrard doesn't have time for players who don't seem 100% up for a challenge.
Gerrard tested Windass by saying he could stay and fight or go to Wigan, Windass chose the latter in a huff. Lafferty, an international and title winner who is 30 years old, saying he was too nervous for the ball doesn't strike me as a person Steven Gerrard would want around.