"He just leaves a vacuum that's going to be very hard for them to fill," Jackson said, according to the Los Angeles Times.
Cuban scoffed Tuesday evening at reporters' questions about whether this affected the Mavs' approach in the trade market. He kept his answers brief, saying they'd be "opportunistic," as always.
But Cuban was a bit more talkative while jabbing at Jackson, poking fun at the legendary coach's romantic relationship with Lakers owner Jerry Buss' daughter and team executive vice president of business operations, Jeanie, in the process.
"I love that Jeanie Buss' boy-toy had something to say about us," Cuban said while sweating on the stair-stepping machine in the Mavs' workout room. "I don't know if it was his thought or Jeanie's thought, but it's nice to know that she lets him speak in public about other teams."
When asked about Cuban's comments, Jackson said, "Mark must be really worried. If he's got to comment on that, he must be really worried."
At age 65, Jackson took Cuban's jab as a compliment.
"I love it," Jackson said. "I consider myself an old man, to hear that I'm a boy-toy? That's terrific."
Buss, meanwhile, told reporters there could have been a better comeback by Cuban.
Jackson then tried to clarify his original comment about Dallas.
"I feel badly for [the Mavericks], that's what I was saying. It's hard to replace a player that good," Jackson said. "They do have a good player that's sitting behind him. Shawn [Marion] is a fine player, but it's not Caron Butler, so it's hard to replace a player like that."
Cuban declined to offer his opinion on the two-time defending champion Lakers, who have hit a rough patch with four losses in six games.
"I don't have a take on his team," Cuban said with a smirk. "I like Jeanie."
Tim MacMahon covers the Mavericks for ESPN Dallas. You can follow him on Twitter or leave a question for his weekly mailbag. Information from ESPNLosAngeles.com's Dave McMenamin was used in this report.