Former Timberwolves general manager David Kahn will vouch for two things regarding Michael Beasley — he will light up the Garden as “an incredibly gifted natural scorer’’ and Knicks assistant coach Kurt Rambis is a huge fan. Beasley is in Tarrytown, reporting for Knicks’ voluntary workouts ahead of training camp, which opens Monday. Potentially serving as Carmelo Anthony’s eventual replacement, Beasley signed a one-year deal for the $2.1 million veteran’s minimum last month. In 2010, Kahn traded for Beasley and has no regrets. Kahn, who teaches sports management courses at NYU, obtained Beasley, the second overall pick of the 2008 draft, after two seasons with the Heat. Kahn gave up two second-round picks and cash, then created waves when he said in a mostly misinterpreted radio interview that Beasley was “a very young and immature kid who smoked too much marijuana.’’ As it turned out, marijuana was not an issue in Beasley’s two seasons in Minnesota. Failure to grasp defensive concepts was the problem that led to their divorce.