Brown was forced to pay out Ricciardo early on his contract, which had been meant to fall due at the end of the 2023 F1 season. He will be replaced by highly-rated countryman Oscar Piastri alongside Lando Norris for next year.
This all means that Ricciardo will likely miss the 2023 season unless another team comes forward to sign him up for next year.
In an interview with Kayo Sports at the Bathurst 100, Brown explained how the McLaren team had tried everything to get the struggling Ricciardo comfortable and up to speed in the McLaren.
"Ultimately we weren't getting the results that we needed and we're a year-and-a-half into this," Brown said. "We've all tried extremely hard, we love Daniel, he's great to work with and continues to be great to work with.
"But we're in the results business and the results weren't coming and we felt we tried everything. We don't really know why it didn't click, it's kind of nobody's fault. We gave it our best. He gave it his best … we just kind of ran out of things to try.
"Sometimes athletes go into slumps or need a change of environment," Brown added.
When Ricciardo joined the British team from Renault in 2021, he arrived with big expectations but his fall from grace to where he is now at McLaren is almost unprecedented in the sport. Many believe his big career mistake was to leave Red Bull for the promises of Renault and the big money offer on the table.
Brown said he always admired the racer in Ricciardo and wanted him since before he joined Renault: "I tried to get Daniel before he went to Renault, so this was years in the making. I'm a huge Daniel fan. I'm still a huge Daniel fan and that'll never change," Brown said.
"I asked him if he wanted to drive for us in the IndyCar or Formula E… I'd love to keep Daniel in the family but he's still very focused on F1, which I get, it's the pinnacle of motorsports. I'd love to race with him again."
Ricciardo's final race in Abu Dhabi next month, will be his 240th race start with 32 podiums including eight F1 wins.