Shams Charania of Yahoo Sports added the ailment could cost Thompson "several games", but he's expected back by month's end. He will be re-evaluated on March 22.
The injury - originally believed to be a simple sprain - will keep Thompson out for at least four more games.
In either case, Thompson is sidelined by an injury sustained in the fourth quarter of a loss to the Timberwolves on Sunday in Minnesota.
Apple Inc. (NASDAQ:AAPL) Shares Sold by Papp L Roy & Associates
It is positive, as 52 investors sold AAPL shares while 1034 reduced holdings. 116 funds opened positions while 640 raised stakes. After $3.89 actual EPS reported by Apple Inc. for the previous quarter, Wall Street now forecasts -30.08% negative EPS growth.
Thompson, 28, is averaging 19.7 points and shooting at a 44 percent clip from distance on the season.
Injuries to these three All-Stars are not considered to be serious, sources said.
This is a clear sign the defending champions are valuing health heading into the playoffs, rather than making a run at the No. 1 seed.
Golden State is now 8-2 in their last 10 games, but trailing the Houston Rockets by two full games in the race for first place in the West.