The 30-year-old was unable to start at The Hawthorns but was named as a substitute. However, he did not see any action.
Boss Nigel Clough said: "Rob could not start against West Brom because his back was too sore. If he had strained his back worse it could have led to him missing more than one game. There was no point risking that with 13 games to go.
"He will have a gentle start to the week and should be training towards the end of it ahead of the game against Watford at the weekend."