Why the Cavaliers would do this
Since Donovan Mitchell landed in The Land, there have been questions about his desire to stay in the Midwest. One of the looming questions is whether he wants to go to a bigger market. Some NBA executives think it's championship or bust for Mitchell to stay in Cleveland. They are not going to win the title this year, so Tyler Herro may be the best player you can get with Mitchell on an expiring deal.
Herro would fit with Darius Garland, as DG would return to the lead guard role. He hasn't played his best basketball in the last few months, but putting the ball back in his hands would resurrect his career. He and Herro would be a deep-shooting, flame-throwing backcourt that would torch teams in the central division for years to come.
Not to mention the draft capital Cleveland would acquire in this deal, a nucleus of Garland, Herro, Evan Mobley, Jarret Allen, and draft capital is appealing.
Trade grade for the Cavaliers: B