The Chicago Sun-Times learned before the 4-3 win over the Blue Jays that Guillen and Reinsdorf agreed to part ways, with a trade to the Florida Marlins likely to be announced Wednesday.
The White Sox reportedly will receive two minor-leaguers.
"We certainly cannot thank Ozzie enough for all he has done during his eight seasons as manager of the Chicago White Sox, highlighted by an unforgettable 2005 World Series championship," Reinsdorf said in a statement.
"I personally appreciate everything he has done for this organization, our fans and the city of Chicago. We shared the greatest moments together and wish him nothing but future success in baseball and in life."
Said Guillen: "I will be Jerry's friend forever. This business move will not change our relationship."
According to sources, the meeting with Reinsdorf was emotional on both sides, as the two men wanted the end to come on good terms.
The end with general manager Ken Williams? Not so much.
"Me and Kenny don't have the best relationship the last couple of years," Guillen said after the game. "But we never put that thing between us. ... I don't have anything against Kenny."
The White Sox and Marlins weren't able to announce the deal just yet, but Guillen was scheduled to fly to South Florida on Tuesday morning.
"There is something in place in the event that one particular team gets him," Williams said, "but he's free to negotiate with anyone."
It was first reported by the Sun-Times last October that the Sox and Marlins were in talks about a deal for Guillen, after it was obvious that Guillen and Williams were heading for irreconcilable differences.
Those differences began shortly after the 2009 season, and they snowballed.
At the time of the original talks, the Marlins didn't feel as if they needed to give up talent for Guillen, especially with a new ballpark under construction that wasn't opening until 2012. Things have changed, obviously. Guillen and Williams have stayed politically correct in addressing the media about each other the last few weeks, but more for Reinsdorf's sake than the truth.