2:57 PM ET Adrian WojnarowskiSenior NBA Insider Close Host of The Woj Pod Joined ESPN in 2017 Phoenix Suns restricted free agent center Deandre Ayton is signing a four-year, $133 million maximum contract offer sheet with the Indiana Pacers , his agents, Bill Duffy and Nima Namakian, told ESPN on Thursday. The Suns have two days to match the largest in NBA history and keep Ayton -- or let him go to the Pacers for nothing in return. Ayton's offer sheet surpasses the four-year, $107 million deal signed by Otto Porter Jr . with the Brooklyn Nets in 2017 -- a deal the Washington Wizards ultimately matched. Sign-and-trade deals are no longer allowed once Ayton signs the offer sheet with Indiana. If the Suns do match the offer sheet, they can't trade Ayton anywhere until at least Jan. 15 -- and can't trade him to Indiana for a year. Deandre Ayton averaged 17.2 points and 10.2 rebounds this past season with the Suns, shooting 63.4 percent from the field and 74.6 percent from the foul line. Mark J. Rebilas/USA TODAY Sports Namakian of Innovate Sports and Duffy of BDA Sports and WME had insisted to the Suns that they could find a maximum contract offer for Ayton in the marketplace, and are now delivering it with the offer sheet. The Suns had never made Ayton an offer, suggesting that they didn't value him as a max player. If they don't match the sheet, they Suns will lose the No. 1 overall pick without compensation. The biggest offer sheet signed by a team that wasn't matched was when Harrison Barnes was signed by the Dallas Mavericks for four years and $94.4 million in 2016, the same summer Barnes' former team, the Golden State Warriors , signed Kevin Durant as a free agent. Ayton, who turns 24 next week, was drafted with the first overall pick in the 2018 NBA Draft out of Arizona, part of a star-studded draft class that included Luka Doncic (third), Jaren Jackson Jr . (fourth), Trae Young (fifth) and Shai Gilgeous-Alexander (11th). Editor's Picks What every NBA team can and can't trade this offseason 1d Bobby Marks Five Donovan Mitchell trades we want to see 3h NBA insiders 2 Related After making the All-Rookie first team in 2019, Ayton has developed into a quality starting center, averaging 16.3 points and 10.5 rebounds per game while helping anchor Phoenix's defense during its run to the 2021 NBA Finals -- the first time the franchise has reached the league's championship round since Charles Barkley led the Suns there in 2023. He averaged 17.2 points and 10.2 rebounds this past season, while shooting 63.4 percent from the field and 74.6 percent from the foul line. After an outstanding regular season, finishing with the league's best record, Phoenix's postseason ended with a blowout loss to the Mavericks in Game 7 of the Western Conference semifinals -- a game Ayton spent most of the second half watching from the bench. When asked why that happened after the game, Suns coach Monty Williams said, "It's internal." Ayton, meanwhile, declined to talk to reporters after the game. Indiana traded Malcolm Brogdon earlier this offseason and Domantas Sabonis last season, shifting into a new era centered around an exciting young backcourt of emerging star Tyrese Haliburton and rookie Bennedict Mathurin , the sixth pick in last month's NBA Draft out of Arizona. ESPN's Tim Bontemps and Bobby Marks contributed to this report.