Rivers, like Budenholzer, had previously been NBA named coach of the year (though Rivers had the added cachet of winning the 2008 NBA championship with the Celtics). The Celtics then, like the Hawks now, were entering a rebuilding period and Rivers in 2013, like Budenholzer in 2018, decided to look elsewhere.
At the time, Rivers had three years and $21 million left on his contract. The Celtics got an unprotected first-round pick in the 2015 draft from the Clippers, which ended up being the No. 28 overall pick. (Boston used it to select former Georgia State star R.J. Hunter.)