The 28-year-old keeper, who played under City boss Gary Johnson during his time at Yeovil Town, has joined City on a short term deal until the end of the season having been released from his contract with Crewe at the beginning of the month.
"Steve is a player I know very well from my time at Yeovil and he is a very capable keeper," Johnson told the club's official website.
"Steve contacted us after leaving Crewe and asked if he could come training and he's been with us for a few weeks now.
"Not a lot of people are aware of his situation and he's sneaked under the radar to an extent. We've got ourselves a very good keeper and he will provide strong competition for Dean Gerken.
"He wasn't No.3 goalkeeper at Crewe, he had a disagreement with them when cutbacks meant they had to go without a goalkeeping coach. That wasn't going to help his game so he looked to move on."