The target is believed to be a wide-sided midfielder, with the Reds in the market for fresh options on the flanks following the big-money sale of Brad Potts to Preston.
Assistant head coach Andreas Winkler said: "We are close to signing a new player. We (recently) lost a player in Brad Potts.
"Everyone in the club is doing their best to give us a strong side."
Meanwhile, Winker has confirmed that midfielder Callum Styles is attracting interest from several lower-division clubs, with a decision on his future likely later this month.
The summer signing recently returned to Oakwell after spending the first half of the season at League Two promotion-chasers Bury and is being monitored by Reds staff ahead of making a decision as to whether he will remain at the club for the rest of 2018-19 - or continue his development with another loan spell.
Winkler added: "It is option to keep him here or look for what is best for the player in the end and what is best for the club.
"We want to see him for two or three weeks. But it (another loan) is an option because of his performances with Bury. Lots of clubs would love to loan him, but it is up to us what we do and we will talk to the player and see what is best."
Midfielder Mike Bahre will miss Saturday's trip to AFC Wimbledon through injury.
The problem is not a serious one and he could return to training next week.
"Mike has a problem and he will not be in the squad," Winkler confirmed.
"We hope he can train next week, but we are not really sure. It is an injury which he has had in his past. But it is not a big thing."