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."
Despite his optimism, the concession of an equaliser in the fifth minute of stoppage time at the Madejski Stadium, as the Blues let a two-goal lead slip, was difficult to fathom from a team that were champions of Europe last term.
Benitez refused to criticise his side and was determined to look to the future.
He said: "After 92 minutes we were in control, 93 and a half we were in control. It's just a long ball and a lack of concentration.
"It's something that we needed to fix. We have been talking about that.
"Just one minute of lack of concentration changed everything. In terms of the performance, the team was really good.
"You have to move forward and hopefully the next time we can do better."
Benitez has had midweek matches in every week of his reign thus far.
Next week's international break will be the first when there is no midweek fixture for Chelsea under Benitez, who will hope his players return healthy.
Benitez played down Fernando Torres' omission from the Spain squad to play Uruguay in a friendly in Qatar - "Spain have some good strikers," he said - and praised Ashley Cole, who is in line to win his 100th cap when England play Brazil at Wembley next week.
While Torres is not in the World Cup winners' squad, right-back Cesar Azpilicueta is, alongside Mata.
With five more games in February after the Newcastle match and the international fixtures, Benitez may be inclined to ask international bosses to use his players sparingly.
"You cannot influence the national managers, it's not easy," he said.
Belgium forward Hazard will be free to play at Wigan a week from Saturday after the Football Association decided against extending his ban for kicking a ball boy during the Capital One Cup semi-final second leg at Swansea.
Hazard was sent off for kicking 17-year-old Charlie Morgan as he attempted to retrieve the ball during the Blues' 0-0 draw at the Liberty Stadium which saw them exit the competition.
It had been suggested that the FA were considering handing down a lengthy suspension, but instead it was ruled that the usual three-game ban for violent conduct should stand instead.
Benitez said: "We knew that could be three games. No more. That's it. We are really pleased."