Blazers president of basketball operations Neil Olshey announced the decision Friday. Portland had until early January to make the deal fully guaranteed for the rest of this season.
Anthony, 35, initially signed a one-year, non-guaranteed contract with the Trail Blazers in mid-November after an extended absence from the NBA. Prior to signing with Portland, he hadn't played since November 2018 with the Houston Rockets.
During his short time with the Trail Blazers, Anthony has strung together strong performances and was named the Western Conference Player of the Week last week after averaging 22.3 points, 7.7 rebounds and 2.7 assists to guide the team to a 3-0 record.
It marked the first time Anthony earned Player of the Week honors since the 2014 campaign, while he was playing for the New York Knicks.
In eight contests with Portland, Anthony has averaged 16.9 points, 5.9 rebounds and 1.8 assists per game. He poured in 20 points in 36 minutes during the Blazers' 127-116 win over the Sacramento Kings on Wednesday night.
The Trail Blazers (9-13) will play the Los Angeles Lakers (19-3) at 10:30 p.m. EST Friday.