Celtics’ Leandro Barbosa carried off court, Kevin Garnett tells media guard done for season (VIDEO)

The Boston Celtics lost for the first time in more than two weeks when they fell to the Charlotte Bobcats on Monday, but they may have suffered a much more serious loss late in the third quarter, when reserve guard Leandro Barbosa pulled up with a non-contact injury, fell to the floor in apparent pain and had to be carried off the court by Celtics trainer Eddie Lacerte and teammate Fab Melo:

With just over 35 seconds left in the third quarter and the Celtics trailing 75-70, Barbosa dribbled up the court looking to initiate some late-stage Boston offense. He passed half-court and drove hard to the left around a perimeter screen by Jeff Green, but found his path to the rim impeded by on-ball defender Ramon Sessions and rotating big Brendan Haywood. Barbosa stopped short at the baseline, planting hard on his left leg to stop his momentum, then pivoted and kicked the ball back out to backcourt partner Jason Terry.

As Boston continued to work the ball in search of a shot attempt, Barbosa could be seen hopping and hobbling, eventually going to the floor out of bounds along the baseline; the Celtics fouled after the Bobcats brought the ball down the court in a 5-on-4 situation, and Barbosa was helped off the floor with 11.7 seconds remaining in the quarter. He would not return, finishing with three points, three assists and two rebounds in 12 1/2 minutes in Boston's 94-91 loss.

After the game, Celtics coach Doc Rivers said Barbosa will have an MRI on his left knee on Tuesday, assessing the situation soberly but leaving some room for optimism: "It doesn't look great but we'll see." All-Star center Kevin Garnett, however, offered a dimmer view, according to CSNNE.com's A. Sherrod Blakely:

"We're falling like flies right now [...] It's tough. It's just tough all the way around. You messing around with these guys and then all of a sudden you see a season-ender, season-ending injuries ... it's tough, man. We're grinding right now."

When asked later if he was pretty much being told that Barbosa's season is over, Garnett responded, "pretty much."

Steve Bulpett of the Boston Herald followed Tuesday morning with more grim reporting on Twitter:

More sources saying what we've already been hearing: Testing being done, but it's looking like an ACL for Barbosa.

— Steve Bulpett (@SteveBHoop) February 12, 2013

Source on whether Barbosa has ACL tear: "They have to do the tests to verify it, but that's what it looks like."

— Steve Bulpett (@SteveBHoop) February 12, 2013

While no definitive diagnosis can be made until the doctors get a look at the results of that MRI, a season-ending ACL tear to Barbosa would be Boston's second in less than three weeks, following the Jan. 25 injury to All-Star point guard Rajon Rondo. It would also make Barbosa the third key Celtic in three weeks to go down for the remainder of the season, after Rondo and rookie big man Jared Sullinger, who needed surgery to repair a back injury.

After struggling to find a home this offseason after playing for his native Brazil in the 2012 Summer Olympics in London, Barbosa joined the Celtics two weeks before the start of the season and offered some offensive punch off the Boston bench for the first month of the season, averaging 6.3 points and 1.5 assists in 14.3 minutes per game through the C's first 17 contests, shooting a sterling 41.7 percent from 3-point range. He fell out of Rivers' rotation amid the Celtics' December and January struggles, though, averaging just over six minutes a night between Dec. 5 and Jan. 25 as he lost burn to the likes of Terry, Courtney Lee and returning starter Avery Bradley. At the same time, Barbosa was experiencing real-life struggles off the court, as his mother-in-law suffered with kidney problems, falling into a coma and desperately needing a transplant.

While he'd played less than 20 total minutes in three straight late January Boston losses to the Detroit Pistons, New York Knicks and Atlanta Hawks, the need to divide backcourt minutes and ball-handling responsibilities after Rondo's ACL tear forced Barbosa back into the rotation, and he had responded well, averaging just under nine points on 46.3 percent shooting and three assists against just one turnover in 22 1/2 minutes per game during Boston's seven-game post-Rondo winning streak. He wasn't frequently providing game-changing play — though he did score 12 of his 14 points in a recent comeback win over the Toronto Raptors in the fourth quarter — but he was an important piece of a Celtics lineup that, in the absence of its primary facilitator, ball-handler and shot-creator, has increasingly relied on three-guard lineups, uptempo play and a many-hands-makes-light-work style of offensive orchestration.

Now, one set of capable hands could be removed from Rivers' equation, adding more questions and chaos to what BDL Editor Kelly Dwyer recently described as "an either/or" Celtics team that's had a four-game losing streak, a six-game winning streak, a six-game losing streak and a seven-game losing streak over the past month and a half, making it increasingly difficult to know exactly how seriously they're to be taken as we head into the second half of the season and move toward the playoffs. Whatever the on-court result, we're hoping for the best for Barbosa, whether that be a better-than-expected outcome on that MRI or a full and speedy recovery if the worst fears are confirmed. Get well soon, Blur.

Video via OfficialCelticsHD.