According to The Athletic's Tony Jones and Fred Katz, Portis is looking to earn up to $16 million annually from his next contract and the Wizards "aren't expected to match a huge offer sheet."
This was one of the risks when Washington acquired Portis from the Chicago Bulls as part of the Otto Porter Jr. trade and why it didn't make a ton of sense to flip a useful rotation player—albeit one who's making $27 million in 2019-20—for somebody on the verge of restricted free agency.
The Wizards would have justified reservations about matching an offer sheet that pays Portis upwards of $16 million a year.
In 28 games with the team, he averaged 14.3 points and 8.6 rebounds and shot 40.3 percent from three-point range. He also had more turnovers (45) than assists (43) and ranked 76th among power forwards in ESPN.com's real plus-minus (minus-1.96) over the course of the entire season.
Portis' market value is ultimately whatever somebody pays him, but his initial contract demand is steep for a player who hasn't started more than 28 games in a season through his first four years.
Pragmatically, letting Portis walk would be the right move for Washington. But that would mean losing a 24-year-old forward on a roster that's largely devoid of long-term foundational pieces.
The franchise is in a holding pattern with John Wall recovering from a ruptured Achilles, and his four-year, $170 million extension makes it difficult to improve the roster for the foreseeable future. If Portis leaves, the Wizards can't really make a corresponding move to find a player of similar age and skill.