The team also said Monday that it has exercised the fourth-year option on guard Ty Lawson.
The Nuggets didn't release the terms.
Afflalo is in his second season with the Nuggets. He had several career highs last season, including points (12.6), rebounds and (3.6), assists (2.4).
Forbes finished his rookie season with averages of 5.2 points and 1.8 rebounds in 63 games.
Lawson became Denver's starting point guard after Chauncey Billups was traded, averaging 11.7 points and 4.7 assists.