SANTA CLARA >> An abundance of injuries may have prompted the 49ers to scrap joint practices with the New Orleans Saints in Irvine, but the games must go on.

At least, Sunday’s 5 p.m. preseason game. It’s the only exhibition Levi’s Stadium will host.

Even without the plethora of joint-practice reps, the Saints still could provide the best measuring stick for how the 49ers look before the regular-season opener Sept. 9.

Cornerback Charvarius Ward didn’t mind skipping the SoCal sojourn, saying: “We would have got the same amount of work in down there as up here. I just like being home better.”

Indeed, the 49ers endured a two-hour practice Thursday on their Santa Clara practice fields, at times pitting their starting units against each other, rather than against the Saints as they wrap up their summer stay at UC Irvine.

Here are some things to watch in the 5 p.m. game

CAMEO FOR STARTERS >> Coach Kyle Shanahan could be tempted to play some of his starters more than usual since they didn’t get to scrimmage the Saints in the preceding days.

Quarterback Brock Purdy is expected to start after sitting out last Saturday’s preseason opener at Tennessee. The 49ers may not want him in there long considering he’ll be without his blindside protection. Left tackle Trent Williams still has not reported to camp, and left guard Aaron Banks underwent pinkie surgery Friday.

Offensive tackle Colton McKivitz, safety Ji’Ayir Brown and guards Aaron Banks and Dominick Puni were the only projected regular-season starters to make cameos in the 17-13 loss to the Titans.

DELAYED DEBUTS >> Brandon Allen started in place of Purdy and ahead of Dobbs in the preseason opener, so the order could flip with Dobbs following Allen this time. But the 49ers have another quarterback on the roster, undrafted rookie Tanner Mordecai, who could be among those making their delayed pro debuts.

Wide receiver Jacob Cowing, tight end Mason Pline and running back Ke’Shawn Vaughn all could see their first offensive snaps. Cowing, a fourth-round pick, has been hindered by a hamstring injury but he could thrust himself into the return-specialist role with some preseason production. Pline played five special teams snaps at Tennessee, so look for him to get a chance at tight end as he vies with Jake Tonges and Cam Latu for the No. 4 spot behind George Kittle, Eric Saubert and Brayden Willis.

RUNNING BACK OUTLOOK >> Running back Christian McCaffrey (calf) has already been ruled out for the preseason, and although he seems to be moving well, the 49ers will turn to their bench, and those way down the bench.

Also sidelined are Elijah Mitchell (hamstring), Isaac Guerendo (hamstring) and Patrick Taylor Jr. (foot). That’s thrust Jordan Mason into the No. 1 role, but he came out after last game’s opening-drive touchdown, and he likely won’t get worn down much in this game. Hence, look to see if the 49ers can find more running room for Matt Breida (six carries, no yards last game), Cody Schrader (five carries, six yards) and Vaughn.

INJURY ALERT >> As well documented, the 49ers are just trying to get out of this preseason as healthy as possible. Last game, they saw major injuries sustained by defensive tackle Kalia Davis (knee), cornerback Ambry Thomas (forearm), and wide receiver Frank Darby (hamstring).

They’ve yet to lose a starter to an injury that is projected to sideline them for the season opener, and that is the unmentioned goal through to the Aug. 23 preaseason finale at the Las Vegas Raiders.

Wide receiver Ricky Pearsall (shoulder) and cornerback Isaac Yiadom (ankle) are wounded newcomers who likely won’t suit up until the regular season, as is the case for safety Talanoa Hufanga, who gained medical clearance Thursday to advance into more football-specific moves in his ACL recovery.

• Working the game for FOX’s broadcast are Adam Amin, Mark Sanchez and Kristina Pink, while Tom Brady reportedly rehearses in another booth for his regular-season broadcast debut.