Solder recently signed a contract with the New York Giants after playing in Foxborough for seven seasons.
"Respect. Hard Work. Dedication. Team. Success. Seven years and thousands of life lessons later I know this much: you are all first class in every Patriot Way," he said in a newspaper ad.
Solder was diagnosed with and treated for testicular cancer in 2014. He and his wife Lexi had a son, Hudson, a short time later. In 2017, solder and his wife had a daughter named Charlie.
When Hudson was a 1-year-old he was diagnosed with kidney cancer. He is recovering after being treated in Boston.
"We will miss you, New England, but we leave here happy with memories, relationships and friends that will last a lifetime. And two super nice rings too!" Solder closed out the letter.