NEW YORK (WFAN) — Hey, maybe that giant birthday card worked.

The Dallas Mavericks, reported to have serious interest in Deron Williams, are “becoming increasingly worried” that the point guard will re-sign with the Nets, according to

The Nets parked a truck outside Williams’ Manhattan apartment Tuesday with the oversized message, “HAPPY BIRTHDAY DERON; from your Brooklyn family.”

The 28-year-old has officially declined his 2012 option, Stefan Bondy of the New York Daily News tweeted Wednesday. The move was expected and means Williams will become a free agent on Sunday.

Williams will reportedly decide between Dallas and Brooklyn when he hits the open market on July 1. Some in the Mavericks’ camp still think there’s a “50-50” shot of landing the All-Star, reported, while others have “detected a real concern.”

Nets general manager Billy King met with the media on Wednesday. Multiple writers were quick to tweet King’s reply after he was asked if he had any worry about Dallas owner Mark Cuban calling Williams.

“Nope,” said King.

Williams joined the Nets in 2011 after six seasons in Utah. The two-time All-NBA second-team selection averaged 21 points and 8.7 assists in 55 games last season.

Is Williams bound to stay with Brooklyn? Be heard in the comments below!

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