Ba has a clause in his contract that will allow him to leave for £7.5m and Arsenal are understood to be among a number of clubs interested in his signature.
The 27-year-old is Newcastle's top scorer this season with 11 goals, and Cisse, whom Ba helped to settle in following his move from Freiburg last January, fears losing that goal threat will be a difficult void to fill.
"I adapted well to playing with Demba Ba when I signed last season and he is a vital player for Newcastle," Cisse told The Sun.
"I hear the decisions from the directors at the club but, personally, I don't think this is good news for us."
While Ba has been in fine form this season. Cisse has struggled in front of goal.
Having scored 13 times in 14 games at the back end of the last campaign, he has only managed to find the net five times in 23 appearances this term.
Cisse admits he has been far from at his best, but is backing himself to have another strong second half of the season.
He added: "My first season was good but this time I've still to hit my best level. But I am optimistic and convinced the fans will soon see the good Papiss Cisse of the past campaign.
"I certainly remember all last season's goals and I am looking to obtain a similar number. This is my objective, but it's not easy."
Cisse's frustration this season reached a head in last week's 1-0 win over Queens Park Rangers, when he reacted angrily to being substituted midway through the second half for Shola Ameobi, who went on to score the winner.
Cisse, who has played most of the campaign out of position on the right flank, barely acknowledged Newcastle manager Alan Pardew as he left the pitch and continued to rant in the dugout.
However, he is adamant he is not an argumentative player.
"I am a Newcastle player and accept the orders of the coach," he said. "I am more of a forward but if my work helps it is normal to play in any position I am asked.
"I have never demanded an explanation from Alan Pardew. I have generated controversies with coaches during my career but Pardew has spoken with me and told me how much confidence he has in my work."