Shea said: "We had an injury and I had to jump right into the game.
"It was all right, I have to get used to it after not playing for four months.
"I've got a bit to go on fitness and getting back playing. I'd say I'm 75 to 80 per cent.
"It's been frustrating. The last couple of weeks have been like my pre-season, trying to get fit but not putting too much pressure on the foot I had surgery on.
"Trying to get touches on the ball as well is a lot to squeeze in."