A source confirmed an NFL.com report to ESPN's Adam Schefter that Gonzalez suffered a strained ligament in the knee and will miss 2 to 6 weeks.
The Colts plan more tests for Gonzalez on Monday and will monitor any swelling.
Gonzalez wasn't touched on the play in which he was hurt. He started his route, then fell to the ground. He was helped off the field and put no pressure on the right leg.
Information from The Associated Press was used in this report.