"First of all, contrary to some reports, the Seahawks didn't ask me to take a pay cut. There was no negotiation. When I met with them on March 7 to discuss my future, they informed me of their intent to release me. They didn't know when they were going to do it, but it would be soon, they said.
"Two days later I was in Las Vegas at the NFLPA meetings, sitting up on a stage in front of like 200 people in a giant hotel conference room, when my phone started blowing up. News of Seattle's plans had gotten out.
"A few of hours later, at about 1 p.m. Pacific, the Seahawks officially released me."
Sherman noted the 49ers called him three minutes after his release became official:
"They wanted me to fly to San Jose to have dinner with Kyle Shanahan. So I got my affairs in order — I had literally been a free agent for only a few minutes — and wrapped up some union business. Then I went back to my hotel with my fiancée, Ashley, and we grabbed our things and jumped on a flight.
"At dinner, Kyle made one hell of a pitch. He has an incredible football mind — he's just a great tactician — and we talked for hours about different schemes and about his vision for the team. He really impressed me."
After negotiating his deal with the 49ers, Sherman—who represented himself this offseason—said Seahawks general manager John Schneider told him to bring his offer back to Seattle so it could have a chance to match it.
"They didn't," he wrote.
When the Seahawks declined to match the offer, Sherman signed a three-year deal which NFL Network's Ian Rapoport reported is worth up to $39 million with the 49ers.
Per NFL Network's Tom Pelissero, Sherman's deal includes a $5 million signing bonus and $2 million base salary with $1 million incentives based on playing time and a $3 million bonus if he makes the Pro Bowl in 2018.
Sherman added playing against the Seahawks twice a year was "definitely a perk" to signing with San Francisco, but he also signed with the 49ers because "they showed genuine interest" in him.
The 49ers are entering next season with high expectations, despite a 6-10 record in 2017. They won their final five games last season when quarterback Jimmy Garoppolo took over the offense.
Coming off a ruptured Achilles that limited him to 10 games last season, Sherman is hoping to lead San Francisco's defense in 2018 as the franchise seeks its first playoff appearance since 2013.