Nelson was checked out by a doctor Monday and is now listed as doubtful for games at Chicago Tuesday and at Minnesota Wednesday.
The ninth-year pro, who was a 2009 all-star, missed Orlando's win over Phoenix Sunday after being hurt in a season-opening victory over Denver Friday,
Nelson had nine points and seven assists in 35 minutes against the Nuggets. The 30-year-old guard has averaged 12.4 points, 5.0 assists and 3.0 rebounds for his career.
The Magic also are without starting forward Hedo Turkoglu, who will miss at least four weeks with a broken bone in his hand suffered against Denver.
Second-year player E'Twaun Moore is starting at point guard in Nelson's absence. He has averaged 14.0 points and 4.5 assists in the season's first two games.