Jimmy Butler Blocks Family from NBA Bubble, 'This Is a Business Trip'

Jimmy Butler says he refuses to let his family join him inside the NBA bubble in Orlando ... because it's a "business trip" and he doesn't want to be distracted!

FOR REAL!

The Miami Heat star explained himself to "NBA on TNT" sideline reporter Allie LaForce -- who passed it along to viewers Monday night while Butler was DROPPIN' 40 on the Milwaukee Bucks.

LaForce said while some players and coaches were excited to finally welcome wives girlfriends and children into the bubble -- people they haven't seen in person in months -- Jimmy was drawing a hard line.

"No offense to families but Jimmy Butler said, 'This is a business trip for me. I’m not messing around.'"

"Everyone wants to have their family, without a doubt. But we’ve been doing this for this long. What’s another couple of months?"

Jimmy concluded, "It is an individual decision and I respect that decision that my teammates make but for me, I’m here for business.”

WOW.

Butler has a baby daughter back home who's about to turn one in October ... but she'll have to chill out before Daddy can celebrate!

Meanwhile, Butler has definitely been handling business -- he played spectacularly Monday night ... and has led the Heat to the Conference Semifinals, where they're already up 1-0 on the mighty Bucks.

Of course, not everyone feels the same as Jimmy -- Toronto Raptors star Fred VanVleet brought his family into the Bubble this week ... and the reunion was ADORABLE!

The NBA has warned players to make sure their guests don't wild out at games -- no cussing, no storming the court, etc.