League sources told ESPN that Thompson could miss up to two weeks. That would force his absence for the next seven games.
The 6-foot-6 sharpshooter suffered the injury during the second quarter of Sunday's loss at the Minnesota Timberwolves, but he continued to play through it.
Thompson had previously missed only one game this season, for a scheduled rest in early January, when the LA Clippers were in town.
Appearing on ESPNLA 710 AM radio alongside his father, Mychal -- a broadcaster for the Los Angeles Lakers, the Warriors' opponents Wednesday night -- Thompson said he hopes to be back sooner rather than later.
"Hopefully only a week; hopefully I'll be back by next Friday," Thompson said during the Warriors' 117-106 victory over the Lakers. "Just sitting up here watching, I miss being down there, man, so I don't want to be out any longer than that."
Warriors coach Steve Kerr chose to look on the bright side in regard to his shooting guard's injury.
"He probably looked more spent recently," Kerr said. "So, I look at this as a positive."
The Warriors will be without their starting backcourt for at least the next three games.
The franchise also announced that point guard Stephen Curry would be sidelined further with a right ankle sprain and that he will be re-evaluated Tuesday. That means the two-time NBA MVP will sit out the next three contests -- Friday at home against the Sacramento Kings; at the Phoenix Suns on Saturday; and at the San Antonio Spurs on Monday.
"I've been through this countless times, but I feel very confident in the approach that we're taking to get to as close to 100 percent as possible going into the stretch run of the regular season and then obviously the playoffs,'' Curry said after his team's shootaround Wednesday.
"I would obviously love to be out there playing every game down the stretch, to be out there with my squad. At this point, there's enough time -- not just me, we have a bunch of guys banged up -- that we all can prioritize health and understand that we need to all be ready to go.''
Kerr further explained the club's wait-and-see approach to Curry's injury.
"We're trying to build up his strength as best we can around the [tweaked right] ankle, and the training staff felt that an extra week or 10 days of intense rehabilitation would put him in a much better position to play through the rest of the year with less risk of spraining the ankle again," Kerr said.
Draymond Green also sat out Wednesday's game with right shoulder soreness.
Injuries to these three All-Stars are not considered to be serious, sources said. The team is erring on the side of caution.
This is a clear sign that the defending NBA champions are valuing health heading into the playoffs over making a run at the No. 1 seed in the Western Conference. Golden State is two games behind the conference-leading Houston Rockets.
"These games are fun when guys who don't ordinarily get to play much, when they get a chance and really contribute,'' Kerr said. "It strengthens the team.''
With so many down, Kerr wanted his healthy players to be loose and let it fly.
"With Klay and Steph out, what's that, about 75 shots that are not going to be available on most nights that are suddenly there?'' he said.
Information from ESPN's Baxter Holmes and The Associated Press was included in this report.