"I hurt my back - I tore a disc - the week before the Leicester game and it was kind of settling down but I was touch and go," Lawes said.
"Then I slept in a not great bed and that just wrote it off. It didn't actually make my back any worse, it just didn't allow me to improve enough to play that game.
"It was just a normal, single bed. It wasn't a bad bed it was just the change in beds when you've got a bad back."
Retallick famously failed to correctly name a single England player when asked during the summer tour to New Zealand in 2014.
The closest he came was Michael Laws, who at the time was mayor of Whanganui, presumably in reference to Courtney Lawes.