The 32-year-old penned a deal at Oakwell until the end of the season and has enjoyed two promotions from the Championship with Stoke City and Sunderland.
Speaking exclusively to Barnsley Player, Liam said, "It's going to be a good experience hopefully I can bring something to the team that will help us survive this year.
"I missed the football here when I left (for Greece) and I'm looking forward to getting back into the thick of it.
"I watched the Championship in Greece on Sky and it gave me fire in my belly again to come back.
"I've had good experiences here with other teams, I just hope I can have that with Barnsley. When I've come I've always got stick off the supporters," joked Lawrence. "Hopefully they'll be behind me this time!"