The Liga champion has long been linked with both the on-loan Napoli shot stopper and the Borussia Monchengladbach man as the club pursues a long-term replacement for Victor Valdes, who is set to depart Catalunya at the end of the season.
"We have been looking for a new goalkeeper since January and are in advanced negotiations to sign someone," Bartomeu told RAC1. "The plan is to announce who will be our new goalkeeper in January, when Valdes makes his imminent exit official. Ter Stegen and Reina are among the few candidates still on our list.
"We intend to sign just one goalkeeper and not two."
The 31-year-old Reina has a contract with parent club Liverpool until June 2016, but his long-term future at the club remains in doubt after the Reds signed Simon Mignolet during the summer.
Ter Stegen, meanwhile, has a deal with Gladbach until the summer of 2015, but the Bundesliga outfit is keen to hold on to the 21-year-old and have offered him a new and improved contract.