The 2020-21 NBA season will see the Boston Celtics look to overcome last year's playoff disappointment, as they lost the Eastern Conference Finals against the Miami Heat. NBA Rumors suggest the Celtics front office is looking to go big this offseason, and a deal for Tristan Thompson is already in place. On that note, let's take a look at the latest update regarding the 17-time NBA champions.NBA Rumors: Jayson Tatum agrees on a 5-year extension with Boston CelticsMiami Heat v Boston Celtics - Game FiveThe Boston Celtics have a strong roster and will be one of the prime contenders for the NBA championship next season. The team has two young talents in Jayson Tatum and Jaylen Brown, with good role players and veteran presence around them. Head coach Brad Stevens will also have experienced center Tristan Thompson to rely on next season. Boston Celtics v Miami Heat - Game SixAlso read: NBA Trade Rumors: Crucial hours ahead for Washington Wizards as reports indicate John Wall and Bradley Beal disinterested in playing together againThe Boston Celtics have been handed a boost in their attempt to secure the future of their best player, as NBA Rumors indicate Jayson Tatum has signed a 5-year, $195 million extension. Tatum is an integral part of the Boston Celtics' starting lineup and has shown immense potential since he was picked by the franchise in the 2017 NBA Draft. The youngster announced his arrival on the big stage when an inexperienced Celtics team managed to take Lebron James and the Cavaliers to seven games in the 2018 Eastern Conference Finals. The Celtics were without their two biggest stars, Kyrie Irving and Gordon Hayward, and Tatum rose to the occasion in their absence. Tatum gets the full designated rookie max extension, with the All-NBA escalators that'll take it near $200M, sources said. Tatum's agent Jeff Wechsler and Celtics finalized details today. https://t.co/SfGjPRc3J5— Adrian Wojnarowski (@wojespn) November 22, 2020This offseason has been headlined by some mega-money extensions for the 2017 NBA Draft class, with D'Aaron Fox, Donovan Mitchell, and now Jayson Tatum signing new deals. NBA Rumors suggest that Miami Heat's Bam Adebayo could be next in line to sign a max extension. The Boston Celtics recently lost Gordon Hayward to Charlotte Hornets, which places extra responsibility on Jayson Tatum's shoulders for next season.One more deserving rookie max extension candidate in this 2017 draft class: Miami’s Bam Adebayo. https://t.co/GMCFdTUq2t— Adrian Wojnarowski (@wojespn) November 22, 2020Also read: NBA Trade Rumors: Dallas Mavericks express interest in Spencer Dinwiddie; New Orleans Pelicans eyeing Chicago Bulls' 4th pick in the draft