Barnsley have made Irish centre-back Conor McCarthy their fourth signing of the summer transfer window.
The 23-year-old began his career with Cork City then moved to St Mirren in 2019, playing 68 games in the Scottish top flight.
He was out of contract in the summer and has signed a three-year deal with the Reds.
McCarthy told the club website: “Now that it’s all signed, sealed and delivered, it’s a great feeling. You only have to take one look around at the stadium, the facilities that this club has, and
I needed no second invitation to sign for a massive club like this.”
McCarthy's arrival follows the signing of fellow centre-back Robbie Cundy earlier in the week.
Michal Helik is expected to leave Oakwell this summer and the future of his fellow centre-back Mads Andersen is also in doubt.