Cardif have completed the signing of Anthony Gerrard from Walsall for a fee around £200,000.
The 23-year-old former Everton youth player moves to Wales on the back of making 157 league starts for the Saddlers. He joins newly-signed centre-back Mark Hudson in compensating for the loss of Roger Johnson to Birmingham.
"I'm really excited about joining Cardiff," he told his new club's official website. "As soon as I heard that Cardiff were interested in me I never gave it a second thought.
"I came down and had a look around and all the facilities here really are top notch, everything is there for us to get into the Premier League and I am really looking forward to being a part of it."