Coutinho is set to join Bayern on loan for the 2019-20 season – the deal including an option to buy the Brazil international – after the German giants and Barca confirmed on Friday that an agreement is in place.
Bayern have been desperate to reinforce their squad following the departures of Franck Ribery and Arjen Robben, and the conclusion of James Rodriguez's loan deal from Real Madrid.
Ivan Perisic arrived after a serious knee injury scuppered Bayern's attempts to sign Manchester City star Leroy Sane, and Coutinho is poised to follow in Munich.
"I don't think he'll need that much time to adapt to our system and ideas," Lewandowski told reporters of Coutinho after scoring twice in Bayern's 2-2 draw at home to Hertha Berlin in the club's Bundesliga opener.
"I think he's the sort of player that can settle in without many problems."
Coutinho has struggled to cement his place at Camp Nou since joining Barca in a reported €160 million (£146m/$177.5m) transfer from Liverpool in January 2018.
The 27-year-old scored five league goals as Barca retained their LaLiga crown in 2018-19, while he managed 11 in all competitions.
It was not all good news following Friday's agreement as Bayern midfielder Renato Sanches vented his frustration with his lack of playing time.
Sanches – who has struggled since joining from Benfica in 2016 – made a brief appearance against Hertha, the Portuguese an 85th-minute replacement for Thomas Muller.
Upset with the situation following two unsuccessful attempts to leave, the 21-year-old Sanches said: "Of course I'm disappointed, it's the second time the club has not let me go, five minutes is not enough for me."
Asked about Sanches' comments, Bayern head coach Niko Kovac added: "I cannot say anything about that, I did not speak to him."
It doesn't get any easier for Bayern, as they attempt to atone for their opening day draw, with their next league fixture coming away at Schalke on August 24.