The NBA says 48 out of 546 players have tested positive for COVID-19 in its first round of testing for the 2020-21 season.

Yeah ... not great.

But, NBA officials aren't panicked just yet -- insisting they expected higher numbers off the bat as players leave their homes to rejoin their teams, according to The Athletic's Shams Charania.

The NBA says players were tested in their team's home market between Nov. 24 and Nov. 30 -- which the league has dubbed "the initial return to market testing phase."

NBA officials did not name names as to who tested positive so far -- but a spokesperson says all COVID positive players have been instructed to isolate in their team's city "until they are cleared for leaving isolation under the rules established by the NBA and the Players Association in accordance with CDC guidance."

Of course, the NBA does NOT plan on playing the 2020-21 season in the bubble environment at Walt Disney World in Orlando this time around ... despite the massive success it enjoyed earlier this year.

The move to host games in various cities isn't going over well with some players and execs including Philadelphia 76ers coach, Doc Rivers, who said he's "very concerned" about a bubble-free season.

Just look at the NFL ... they're not in a bubble and the 2020 season has been a mess -- with a bunch of players, coaches, execs and others testing positive on a fairly regular basis.

NFL games have been pushed, the quality of the play has been questioned ... and several top players have opted out.