Markieff Morris’s toughness will be missed by the Wizards during his absence. (Jonathan Newton/The Washington Post)

Washington Wizards starting forward Markieff Morris, facing felony assault charges in Phoenix, is expected to have sports hernia surgery Friday and could miss at least the NBA preseason.

Morris, 28, recently received the diagnosis, according to a person familiar with the situation, after spending parts of the summer working out in preparation for the upcoming season. In July, Morris traveled to Las Vegas and participated in informal workouts with several teammates. He then returned to Washington and continued his offseason program. Later in the summer, Morris began complaining about deep discomfort as he exhibited symptoms of a sports hernia. Because of the birth of his daughter and the trial, the procedure — expected to be done in St. Louis — was delayed until this week. Wizards training camp opens Tuesday in Richmond.

Morris and four other men, including twin brother Marcus, are facing charges stemming from a 2015 incident outside a Phoenix recreation center. If found guilty, there is the possibility of prison time as well as a minimum suspension from the NBA of 10 games. The Morris brothers and one other defendant have pleaded not guilty. The other two co-defendants pleaded guilty last week to the same charges.

This is not the first time Morris has endured a sports hernia.

In 2010, before the start of Morris’s junior season at the University of Kansas, he had hernia surgery. After that procedure, Morris missed only preseason practices and returned to play in Kansas exhibition games. He went on to start 34 of 38 games and post the best season of his collegiate career. Morris and his brother declared for the NBA draft the following summer.

Now entering his eighth season in the NBA, Morris might begin the year on the injured list, and the timing dampens the start of what should be a promising season for the Wizards.

Among the top Eastern Conference teams, the Wizards boast the most continuity — which the team solidified this summer by re-signing Otto Porter Jr. to a max contract and giving a hefty four-year extension to John Wall. With those two, alongside Morris, Bradley Beal and Marcin Gortat, Washington will return the only starting unit in the East that has already established playoff cohesion with last season’s first-round win over the Atlanta Hawks, as well as taking the No. 1-seeded Boston Celtics to seven games.

Morris, the self-described “enforcer” of the group, provided a crucial ingredient to Washington’s success. Last season, his first full year with the Wizards, Morris was the overlooked X-factor during the team’s bounce-back in the standings. As the team produced a 12-4 record in January, Morris contributed five double-doubles while averaging 17.3 points and 8.6 rebounds through the month. Washington finished the season 49-33, fourth in the conference.

In addition to being a 6-foot-10 power forward who can play inside and out, as well as anchor the second unit, Morris provides the Wizards with a degree of toughness. He breathed life into the first-round playoff matchup when he played bully-ball against then-Atlanta forward Paul Millsap. After the Wizards’ Game 1 victory when Millsap complained of “MMA” tactics masquerading as basketball, Morris declared how Washington might employ “double MMA” for the next game.

In the second round against Boston, Morris showed his mettle in recovering from an ugly ankle sprain in Game 1 and playing the remainder of the series. As the Wizards depended heavily on the starters in Game 7, Morris played nearly 42 minutes and produced a double-double, though Washington lost, 115-105.