The Greek agent for Knicks draft pick Thanasis Antetokounmpo said he’s “amazed’’ his client chose to play in the NBA’s D-League for the $25,000 cap and turn down an offer from an A-Division team in the Italian League, calling it “a big sacrifice.’’

According to agent Tim Lotsos, the Italian club, Varese, offered Antetokounmpo a two-year deal worth $550,000 with an opt-out to join the NBA after one year. Olympiakos in Greece and Sevilla in Spain also offered him deals.

“Amazing isn’t it?,’’ Lotsos told The Post in a phone call from Greece. “To my surprise, he passed on it. He’s very ambitious and determined to make the NBA. It’s a big sacrifice. It could’ve really put him ahead of schedule in his career. I didn’t try to force him. I wanted him to make his own decision.’’

Knicks president Phil Jackson and general manager Steve Mills convinced their 2014 second-rounder that playing in their new D-League club in Westchester would be more beneficial to a future NBA career despite the massive pay cut.

Antetokounmpo, a 6-foot-6 defensive specialist, won’t be on the Knicks’ 15-man roster and is barred from the club’s training camp because he isn’t signed to an NBA contract. The Post reported after the Knicks selected him at No. 51 Jackson didn’t intend to put him on their roster and chose him as a stash player.

“He spoke with Steve Mills and Phil Jackson,’’ Lotsos said. “He felt he’s in their plans in the future. They don’t have room for him on the roster, but they supported the idea of keeping [him] within the system and working and improving. He felt they do have a plan for him but they didn’t guarantee anything for next year.’’

Antetokounmpo was leery of going to Europe since his younger brother, Giannis, is already with the Bucks and their family moved to Milwaukee from Greece. Last season, before Thanasis was drafted, Antetokounmpo played in the D-League.

The high-energy Greek guard played on the Knicks summer league team and looked raw, committing eight fouls in the opener. However, Jackson said his name should be changed from Thanasis to “Tenacious.’’

According to a source, the communication between Thanasis and the Knicks was poor and the Greek energizer was disappointed they didn’t see him fit for the 15-man roster.

In fact, after The Post’s report he would be stashed, Antetokounmpo told another news outlet it was news to him. As recently as three weeks ago, at a rookie orientation camp, Thanasis said he planned to be in Knicks’ training camp.

Antetokounmpo was wrong about that but he still could be in their Tarrytown complex. The new Westchester team — formerly the Erie Bayhawks — may hold its training camp and practices there.

However, Thanasis will not be allowed to practice with the Knicks or work with their coaching and training staffs.

His agent said Thanasis is still “hopeful’’ a roster spot could open late in the season via trades.