The deal includes a player option for the third year, league sources said. The Thunder used their full taxpayer midlevel exception on the agreement.
The commitment eliminates the Thunder from contention for free-agent forward Rudy Gay, who visited with the organization over the weekend. Gay is searching for a larger deal than the Thunder were able to pay him, with Miami, Utah, San Antonio and Brooklyn among the teams still interested, league sources said.
Patterson leaves Toronto for Oklahoma City, where general manager Sam Presti sees Patterson as a floor spacer alongside NBA MVP Russell Westbrook and the team's new All-Star forward Paul George. Patterson chose the Thunder as an opportunity to stay with a contending franchise and play along All-Star players, which he did with Toronto the past four seasons. In seven NBA seasons, Patterson has averaged 7.9 points and 4.7 rebounds per game.
Information from ESPN's Royce Young was used in this report.