The 37-year-old played 45 minutes for the Baggies against Bournemouth earlier this week.
Speaking after the match, the Northern Ireland international said: "It was good to get the old stripes on again after a frustrating time for me.
"Everything went well and the leg is now feeling perfectly normal again. It's been a frustrating period and obviously not ideal having my pre-season interrupted.
"It was an interesting experience. I looked around the team and felt old enough to be everyone's dad.
"But it feels good again. Now it's a question of trying to get that place back in the starting XI. The competition doesn't get any easier with the players we have been signing!"