"Our family has health concerns, most notably our son's ongoing battle with cancer, as well as my own bout with cancer," Solder said in a Twitter post. "We also welcomed a new addition to our family this spring, a baby boy. With fear and trembling, we struggle to keep our priorities in order and, for us, our children's health and the health of our neighbors comes before football."
Giants general manager Dave Gettleman voiced his support for Solder's choice.
"We have great respect for Nate as a person and player," he said in a statement on the team's official site. "When he called today, I told him it is faith, family and football. He is doing what's best for his family."
According to NJ Advance Media's Matt Lombardo, Solder could qualify as "high risk" in the eyes of the NFL. That would allow him to receive a $350,000 salary advance instead of $150,000 for a standard voluntary opt-out. Any player who opts out will have his contract toll as well.
Solder's absence will likely mean 2020 first-round draft pick Andrew Thomas will be the Giants' starting left tackle.
New York selected Thomas fourth overall in April, and he was tentatively slated to start on the right opposite Solder. Now, the former Georgia star will have to play a key role in protecting quarterback Daniel Jones' blind side, leaving the team in need of a new right tackle. Having signed a one-year contract with the team in March, Cam Fleming would be the logical replacement.