The 27-year-old Senegal striker scored 29 goals in 54 Barclays Premier League matches over 18 months at Newcastle, before signing for Chelsea on January 4 for a fee believed to be £7million.
"He's quite confident that he can do well if he plays," Benitez said. "He's training well. He's a professional. He knows that some fans will not be happy, but some fans will understand the situation. He's ready to do his best for the team."
Benitez suggested he would ask Ba for advice on Alan Pardew's team as he bids to improve the Blues' run of three wins in nine matches following 2-2 draws at Brentford and Reading. All nine of those games were in January.
Under the Spaniard, who took charge in November, Chelsea have amassed fewer points from 12 Premier League matches than under his predecessor, Roberto Di Matteo, in the same number of games.
Benitez, though, is adamant third-placed Chelsea will improve, citing the returns of key personnel to back his statement.
Goalkeeper Petr Cech is available again after missing the two draws in the last week with a calf strain, defender John Terry is poised to return to the starting line-up, Juan Mata has shaken off an ankle knock and only David Luiz (calf) and long-term absentee Oriol Romeu (knee) are still out.
Nigeria duo John Obi Mikel and Victor Moses will soon return from the African Nations Cup, while Eden Hazard misses out at St James' Park, serving the final game of his three-match ban for his controversial dismissal at Swansea.
"If you analyse the games that we didn't win, I think we could win all of them," said Benitez, when asked about the inconsistency of results. "The team is doing quite well with the circumstances that we have, with some players not here or injuries.
"The performance of the team has been good. Still in all the games we had chances to win. That is the main thing for me. We have more players, more options and hopefully in the next couple of months we can keep the consistency and we can keep winning games."