Thorn said he first noticed it in December, an indirect reference to an incident in which Kidd sat out a game against the New York Knicks with a migraine, a move some considered a one-day walkout to force a trade.

“Over the course of time it became very evident that his heart wasn’t in it,” Thorn said. “The kind of player he is, if his heart’s not in it then he’s not the same player, and it became evident to me that his heart wasn’t in it anymore. It just wasn’t going to work.”

This is the third big trade involving a Western Conference power as the teams prepare for the stretch run. Before the All-Star break, Shaquille O’Neal was dealt from Miami to Phoenix and Pau Gasol went from Memphis to the Los Angeles Lakers.

“We understand the competition is fierce, but we’re not afraid of the competition,” Mavericks coach Avery Johnson said.

Kidd’s arrival should be a boon to reigning MVP Dirk Nowitzki, providing him with the easy baskets he used to get when teamed with Steve Nash. His presence also will open things up for Josh Howard, plus let Jason Terry spend more time at shooting guard.

Harris’ numbers have gone up in each of his four seasons, helping him earn a five-year contract worth roughly $42 million before this season. However, he’s nowhere near the distributor Kidd is, nor is he liable to get a triple-double. He may eventually have that well-rounded of a game, but the Mavericks decided they couldn’t wait.

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“We feel (Kidd’s) skill set can help us finish stronger, finish games better,” Johnson said. “Obviously he’s not the guy we’re going to lean on for points, points, points, points. He’s going to help us because at the end of games, he just knows how to win.”

Losing Diop hurts Dallas’ front line, as he is the primary backup to starting center Erick Dampier. However, Diop — who is a free agent after this season — had fallen out of favor lately.

Allen was averaging 5.4 points in almost 16 minutes per game for the Nets.

Dallas also announced it waived forward Nick Fazekas, the 34th pick last year.

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