Irving had requested a trade last month, and with LeBron James also possibly leaving the team next year, the Cavs made a move aimed at both short- and long-term interests.
However, the Celtics were in a tricky position with Thomas, who is heading into the final year of his contract and could have demanded a multiyear extension with annual salaries of around $30 million.
In the meantime, Cleveland should be able to compete for a fourth straight Finals appearance and a second championship with those two stars, a rugged veteran in Crowder, and talented holdovers in Kevin Love, Tristan Thompson and J.R. Smith.
Also helping the Cavs lay the groundwork for the future is Zizic, a 6-11, 20-year-old Croatian taken 23rd in the 2016 draft, who showed great promise while playing in Europe last season.
Having signed Gordon Hayward in free agency earlier in the offseason, the Celtics will have a reshaped backcourt featuring the former Jazz star and Irving, with Al Horford, Marcus Morris and Jaylen Brown likely forming the frontcourt.
- Cavaliers make blockbuster trade: Kyrie Irving goes to CelticsCBS News
- Kyrie Irving traded to Celtics for Isaiah Thomas in blockbuster dealSB Nation
- Reports: Cleveland, Boston in “serious” trade talks for Kyrie IrvingYahoo Sports
- Cavaliers send Kyrie Irving to Celtics in deal including Isaiah Thomas, Nets ...ESPN
- Cavaliers, Celtics agree on trade involving Kyrie Irving, Isaiah ThomasOCRegister
- Cavaliers, Celtics agree on deal for Kyrie Irving and Isaiah Thomascleveland.com
- Trade Grades: Cavs Send Kyrie Irving to Celtics for Package Including Isaiah ...Sports Illustrated
- Kyrie Irving Traded to Celtics for Isaiah Thomas, Jae Crowder, Draft Pick, MoreBleacher Report
- Boston bound: Cavs trade Irving to Celtics for Thomas, moreABC News