After two steamy, physical joint practices with the Houston Texans this week, the 49ers will play their second preseason game of 2018 at Houston Saturday at 5 p.m. Last Thursday’s preseason opener saw the 49ers erase a 11-point lead for a late-game comeback win over the Dallas Cowboys, 24-21.

Let’s review the dynamics to watch in Saturday’s matchup.

Starters to “play maybe a little more”

The 49ers offense played just one drive last Thursday, and the majority of the defensive starters played two drives. That workload may increase, though not much, Saturday evening.

“Maybe a little more,” Shanahan said Thursday. “I see it pretty similar to the first game. We’ll feel it out.”

Last Thursday, the Cowboys’ starters outscored the 49ers’ starters, 7-0, via a touchdown on the game’s opening drive. It was a discouraging start for the defense, which allowed two third-down conversions on that opening drive. Jimmie Ward got beat up the sideline for a 30-yard touchdown.

The 49ers offense gained two first downs but ultimately punted. The offensive line struggled in run blocking, and Jerick McKinnon carried the ball three times for negative-four yards. On the positive side, Jimmy Garoppolo hit Richie James and Marquise Goodwin on tough third-down throws under pressure.

Some more storylines to monitor:

• Will the 49ers defense can contain Texans quarterback Deshaun Watson? Cowboys quarterback Dak Prescott scampered up the middle for a 12-yard run on 3rd and 9 to prolong the drive last Thursday. 49ers defensive coordinator Robert Saleh cited a lack of communication on that play.
• Can the 49ers offensive line can hold off Houston’s army of dangerous pass-rushers? Rookie Mike McGlinchey faces the daunting task of containing three-time NFL Defensive Player of the Year J.J. Watt. Whitney Mercilus is also a second-team All-Pro.
• Will Richard Sherman play? Sherman (hamstring) didn’t play in the preseason opener, but he participated in Thursday’s practice at Houston. The 49ers are staying cautious with him. If he is sidelined, Ward will get the start. He will look to bounce back from a poor showing last Thursday.

The right guard battle

A frontrunner at the right guard spot has yet to emerge, much of which is due to past knee injuries to Jonathan Cooper and Joshua Garnett.

Garnett is expected to make his first preseason game appearance of 2018 Saturday. He had missed eight straight practices, and the preseason opener, with a cryptic knee injury before returning this past Sunday. He worked with the first team offense during Thursday’s practice in Houston.

Garnett’s future with the 49ers may depend on how he performs in the ensuing three weeks. It’s very possible he is either the Week 1 starter or left off the 53-man roster entirely.

Cooper, who signed a one-year deal with the 49ers in March, will also make his 2018 preseason debut. He missed the first four training camp practices and sat out of last Thursday’s opener with a knee injury. Cooper started all 13 of his appearances at right guard for the Dallas Cowboys last year.

Mike Person started last Thursday and did not allow a quarterback pressure in 40 snaps. Like much of the offensive linemen, however, Person struggled in run blocking.

New-look backfield

Saturday’s running back group will look different than last Thursday’s.

The 49ers signed six-year veteran Alfred Morris earlier this week after their top two backs, McKinnon (calf strain) and Matt Breida (separated shoulder), suffered injuries that will keep them out until Week 1.

“I wouldn’t have invited (Morris) if I didn’t think he had a chance to make the team,” Shanahan said Monday. “And I do believe he has a chance to make the team here.”

Shanahan said earlier this week that Morris will suit up Saturday, but he will likely play more in the third preseason game. Morris, whose most productive two seasons in the NFL came under Shanahan in Washington, is a tough, physical runner, contrary to the fast, shifty backs that compose the current 49ers’ backfield.

Morris’ competitors for that third running back spot include Joe Williams, Raheem Mostert, and Jeremy McNichols, all of who are expected to play Saturday. Shanahan has cycled Mostert and McNichols in and out of the first-team unit throughout recent practices to give each a look with the starters. Williams has been away from the team for the majority of this week to mourn the death of his brother-in-law.

Williams struggled to find running room last Thursday, rushing 11 times for 27 yards and a touchdown. Mostert rushed eight times for 51 yards, but he lost a fumble. McNichols had three carries for 15 yards.

What’s intriguing about this race is that each running back presents different value. Mostert is one of the team’s top special-teamers. Williams is an explosive, downhill runner who can bust open a big run if the play is blocked well. McNichols is a do-it-all guy. And Morris is a prototypical third-down back, but he presents no special team value.

Fred Warner to get his first NFL game reps

Warner, the 49ers’ third round pick out of BYU, did not play last Thursday, which came as a surprise. He had dealt with a minor chest contusion. But he was a full participant during Wednesday and Thursday practices in Houston. Barring an unexpected setback, he will make his preseason debut Saturday night.

It’s possible he will start at middle linebacker, considering all the recent attrition. Malcolm Smith (hamstring) is not expected to participate much throughout the rest of the preseason to be ready for Week 1. Brock Coyle has dealt with a nagging knee injury throughout the past two weeks. His status for Saturday is unclear.

Warner entered the NFL best known for his rangy, athletic game. He has since impressed 49ers coaches with his intelligence, physicality, and intensity throughout practice. He will get the chance to show those traits in a game setting Saturday.

Will C.J. Beathard fare better?

The importance of a quality backup quarterback can not be overstated enough. Beathard inherited an awful situation last year when he was thrust into the starting job as a rookie. He led the 49ers to their first win of the year and eventually won over his teammates with toughness amid injuries.

But he has struggled with consistency. Last Thursday, Beathard went 10 for 20 with 181 yards and an interception. He connected with rookie receiver Dante Pettis for a 53-yard completion. Third-stringer Nick Mullens, conversely, completed 11 of his 13 passes, including seven straight throws on the game-winning drive.

The gap between Beathard and Mullens for the No. 2 spot is likely too wide for one preseason game to close it. This is more about Beathard proving he can be consistent.

He logged 40 snaps in the preseason opener. He will likely see around the same workload Saturday.