Despite his obvious disappointment, Sangakkara is confident that Farbrace will be a big help for England as they look to recover from a difficult few months on tour.
"He could understand how Sri Lanka works and his impact was really important for us in those three months," the 36-year-old told Sky Sports News.
"It's unfortunate, the circumstances surrounding how he left, it was probably not nice, but England will gain hugely from Paul.
"He's a top guy and a wonderful coach. He's very good with people and sometimes that's more important than having all the knowledge in the world."
Sri Lanka arrive in England next week for a Twenty20 game, five one-day internationals and two Test matches.