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Grant Williams’ confidence can be traced back from his negotiations with the Boston Celtics last offseason.

As such, he reportedly turned down a four-year rookie scale extension worth around $50 million with the Celtics brass, per Jared Weiss of The Athletic.

“Williams’ representatives and the team discussed an extension before the season that could have reached the low-$50 million range over four seasons but could not agree on the guarantee structure, league sources with knowledge of the negotiations said,” Weiss wrote.

Williams’ rejection of this figure makes him a restricted free-agent this upcoming summer. Should there be a team that offers him a deal, the Cs have their chance to still retain him and deliver a counter offer.

But it can only be determined if the young big man can convince Brad Stevens and the club that he is deserving for a lucrative money and retainment, as he is averaging a career high 8.4 points and 4.8 boards this year.