An inexperienced interim coach, roster battles, and more story lines to watch as the Celtics open training camp Tuesday

Longtime stalwarts Marcus Smart (left), Jayson Tatum (center), and Jaylen Brown (right) are all back, but there's still plenty of uncertainty surrounding the Celtics as they open training camp Tuesday.Jim Davis/Globe Staff

It remains to be seen how Celtics coach Ime Udoka’s one-year suspension for violations of team policies will affect the team’s quest for a championship. Oddsmakers have mostly shrugged, with Boston remaining the favorite to win the title. But the only certainty at this point is that the season will go on without Udoka. Here are six story lines to watch as training camp begins Tuesday.

Is Mazzulla ready?

Interim head coach Joe Mazzulla has had a rapid rise. Just over three years ago he was the head coach at Division 2 Fairmont State, and last spring he was not even one of the three Celtics assistant coaches with a seat on the bench.

But Boston’s brass has been impressed by Mazzulla, and his status as a rising star was affirmed when he interviewed for the Utah Jazz’s head coaching opening this summer. That job went to Celtics assistant Will Hardy, and Mazzulla was promoted to a bench role on Boston’s staff.

Now, he is in charge. During a news conference to discuss Udoka’s suspension Friday, Celtics president of basketball operations Brad Stevens gushed about Mazzulla’s coaching acumen. And this is his fourth year with Boston, so the transition should be relatively smooth.

But unlike Udoka, Mazzulla never played in the NBA, and he is just 34, two years younger than starting forward Al Horford. He has some off-court issues to address, too, most notably his 2009 arrest on charges of domestic battery after allegedly grabbing a woman by the neck at a bar. Stevens said he thoroughly vetted Mazzulla’s situation before hiring him as an assistant in 2019, and he said Mazzulla is prepared to discuss the incident during media day Monday.

There is certainly no guarantee Udoka will be back next year, so Mazzulla could be auditioning for a long-term contract.

Roster battles

As Stevens built the back-end of the camp roster this summer he prioritized veterans who never blossomed with other NBA teams over young, undrafted free agents looking to prove themselves.

Former first-round picks such as forward Noah Vonleh (No. 9 pick, 2014), forward Luka Šamanić (No. 19, 2019), forward Justin Jackson (No. 15, 2017), and center Mfiondu Kabengele (No. 27, 2019) are among those who will be battling for the final three regular roster spots, although Boston will likely keep one open to maintain flexibility.

There is extra urgency, and opportunity, in the frontcourt now that forward Danilo Gallinari is out for the year after tearing an ACL and center Robert Williams is expected to be sidelined 8-12 weeks after undergoing a maintenance surgery on his left knee.

Wing Brodric Thomas and forward Jake Layman could also be in the mix, and the Celtics will monitor training camp cuts elsewhere as the preseason unfolds. For now, they’ve shown no interest in adding a veteran big man such as Dwight Howard or DeMarcus Cousins.

The Celtics will look to Sam Hauser to help fill the role Danilo Gallinari was slated to play as a sharp-shooting offensive big off the bench.Charles Krupa/Associated Press

Hauser time?

Gallinari, 34, was expected to play about 20 minutes per game and provide much-needed scoring pop off the bench. Celtics executives did not panic when he was injured playing for Italy in EuroBasket earlier this month because they are confident second-year sharpshooter Sam Hauser can step in.

The 6-foot-7-inch Hauser made 19 of 44 3-pointers (43.2 percent) while on a two-way contract last season and signed a two-year deal in July. He is limited defensively, but so is Gallinari. Hauser will get early chances to show that he is ready for meaningful minutes.

Backcourt chemistry

Guard Malcolm Brogdon has said all the right things since being acquired from the Pacers in July. He is prepared to be the sixth man backing up reigning Defensive Player of the Year Marcus Smart, and he believes the two will thrive when they are paired together. But they’ve both been starting point guards for much of their careers and both have big personalities. Their cohesion will be essential, and it will be worth keeping an eye on.

Grant Williams extension

Grant Williams could end up being the biggest beneficiary of the injuries to Gallinari and Robert Williams. The durable fourth-year forward is eligible to sign an extension until Oct. 18, and he showed his value as a dependable bench piece last season, when he hit 41.1 percent of his 3-pointers and was an impactful defender.

Williams could command a salary of about $10 million-$12 million per year, or he could look at the larger role looming due to the frontcourt injuries and place a bet on himself heading into restricted free agency next summer.

Stevens’s involvement

Last season, his first as president of basketball operations after spending eight as coach, Stevens went out of his way to give Udoka space to operate. This year could be somewhat different, however, given the sudden transition to Mazzulla, who is much younger and less experienced than Udoka. Stevens will certainly not meddle, but look for him to be more of an adviser and sounding board regarding coaching strategy, especially early in the season.