stick one's neck out

John GrishamのPlaying for Pizzaを読んでいます。
"I'm happy here, Rat." There was a pause as Rat caught his breath. Rick could see him in the locker room, at halftime, pacing frantically and talking wildly as both hands thrashed the air, then a sudden stop for air as he sucked in mightily before launching into the next tirade. An octave lower and trying to sound wounded, he began, "Look, Ricky, don't do this to me. I'm sticking my neck out. After what happened in Cleveland, well--"
"sticking my neck out" は慣用句に違いありません。辞書で確かめます。
・Oxford English Dictionary: informal Risk incurring criticism or anger by acting or speaking boldly.: As I half anticipated, he did not wish to stick his neck out and implicitly criticise rugby.
・Merriam-Webster's Online Dictionary: to do or say something one thinks is important even though it may have bad results: He's not afraid to stick his neck out to help people he thinks are being mistreated.