The Mavericks, looking for an edge in the glove-tight Western Conference playoff race, acquired perennial All-Star Jason Kidd and throw-ins Malik Allen and Antoine Wright from New Jersey for a package of players including Van Horn, draft picks and cash.
In exchange for Kidd, Allen and Wright, New Jersey acquired Devin Harris, DeSagana Diop, Trenton Hassell, Maurice Ager, Van Horn, first-round picks in 2008 and 2010, and $3 million.
To make the trade meet league salary requirements, the Mavs signed Van Horn to a $4.3 million contract before shipping him to New Jersey.
It didn't matter than Van Horn hasn't played in the NBA since the end of the 2005-06 season.
It didn't matter than he is 32 years old.
The Mavs and Nets needed Van Horn, whose new contract will pay him $75,439 per day over the final 57 days of the regular season, or $148,275 for each of the Nets' final 29 games.
Before the NBA would approve the deal, league officials had to be convinced by agent David Falk and his client that Van Horn would report to New Jersey and make an honest attempt at a comeback.
If he can work his way into shape and play for the Nets, Van Horn might help his new team's push to qualify for the Eastern Conference playoffs.
The No. 2 overall pick in the 1997 draft - San Antonio's Tim Duncan went No. 1 - Van Horn averaged 16 points and 6.8 rebounds in 575 career games.
Van Horn was eligible to be traded by Dallas because he had not filed his official retirement papers with the NBA.
In Salt Lake City last weekend to be honored as one of the 16 greatest players in University of Utah history, Van Horn told reporters he simply "forgot" to do the paperwork.
As it turned out, that lapse in memory helped Van Horn receive an unexpected windfall - much like "retired" Aaron McKie did two weeks ago when he was signed to a $750,000 contract by the Lakers just so they could complete a trade with Memphis for Pau Gasol.