Steve Nash sat out the second half of the Lakers' 113-90 loss to the visiting Minnesota Timberwolves on Sunday night because of back pain.
According to a team spokesman, Nash will be examined Monday by back specialist Dr. Robert Watkins.
Nash played 13 minutes, scoring two points without hitting a field goal in three attempts. He also had three assists and two turnovers.
The Lakers have kept Nash out for two games this season as a precautionary measure -- opting for rest when the team plays on back-to-back nights.
Last season, Nash sat out 32 regular-season games, most after breaking his leg in the second game of the year.
Steve Blake, who has found a regular role starting at two guard for the recovering Kobe Bryant (Achilles'), has started at the point in Nash's absence. Jodie Meeks has filled in at shooting guard.