The Padres held an $8.5 million option on Young and the decision to pass on picking it up was not unexpected.
However, Young's free agency does not preclude him and the Padres from negotiating a new contract, and Young said he'd like to remain with the Friars.
"I have no idea who is interested," Young told the San Diego Union Tribune. "The Padres are my first choice as far as I am concerned. I am hopeful something will be worked out.
"While I am hopeful things will work out with San Diego, if not, I am so lucky to have spent five years in the best city in America, playing before tremendous fans and for a first-class organization."
Young, 31, was 2-0 with a 0.90 ERA in four starts last season, including 1-0 with a 1.29 ERA in three starts in September. He missed most of the season with a strained right shoulder.
San Diego general manager Jed Hoyer said last month that he wouldn't rule out the possibility of Young returning in 2011 on a lesser deal.
"I was really impressed with the way he came back," Hoyer said. "He came back, pushed through and made big starts for us."
Young was 33-25 with a 3.60 ERA in 97 starts for the Padres over the past five seasons, a time of which he is fond, according to the Tribune.
"Not picking up the option in no way impacts my feelings and sentiments towards the San Diego Padres," Young said. "The past five years have been five of the best years of my life."
Young went 11-5 in 2006, his first season with the team, and was named to the National League All-Star team the following season.
He was limited to 18 starts in '08 after he was hit in the face by a line drive off the bat of Albert Pujols in May. He spent time on the disabled list later that season with a strained right forearm.
In '09, Young made 14 starts, going 4-6 with a 5.21 ERA. He missed half the season with a strained right shoulder -- one he underwent arthroscopic surgery on after the season.
This season, Young tossed six scoreless innings against Arizona in the second game of the regular season, but complained of shoulder soreness afterward. He was placed on the disabled list, where he remained until he was reinstated on Sept. 18.
Young pitched well in September and didn't allow more than one run in any of his three starts after coming off the DL. On Sept. 29, he allowed three hits in five shutout innings in a 3-0 victory over Cubs at PETCO Park.