SANTA CLARA – The first exhibition game of the season is rarely about the starters, and 49ers' summer unveiling will be no exception.
Quarterback Jimmy Garoppolo and the 49ers' healthy starters on both sides of the ball are expected to see limited action -- one series or two -- Thursday night when the pre-cuts version of the Dallas Cowboys comes to Levi's Stadium.
It will be a notable evening for many of the team's young players who are either battling for spots on the roster or roles for the regular season.
Here are four 49ers players to watch in the preseason opener:
RB Joe Williams
The 49ers' top two running backs appear set with Jerick McKinnon and Matt Breida. Talent-wise, Williams might be their equal. Now, he must prove to the team's coaching staff that he has the "urgency" to turn his potential into reality.
Coach Kyle Shanahan has been quite blunt about Williams, a fourth-round draft pick in 2017. Shanahan saw very little outside his talent last summer that convinced him Williams could be an NFL keeper. This summer, however, Williams is playing with more aggression. He and Raheem Mostert, an ace on special teams, are competing for the No. 3 job.
"I'm just excited to watch him play out on the field," Shanahan said. "I'm a lot more excited now than I was last year, just because of what he's shown in practice.
"He's come a long way in a year, and he's given himself a chance to be a good running back. We'll see how he looks on Thursday."
FS D.J. Reed
Reed, a fifth-round pick from Kansas State, is a versatile defensive back who also can make a contribution in the return game. After playing cornerback in college, Reed has lined up at free safety during his first summer in the NFL. Then, in nickel situations, he moves down to cover the slot receiver.
"He's got a great mindset, a great mentality," 49ers defensive coordinator Robert Saleh said. "He's fighting. We're asking him a lot for a rookie to learn free safety and nickel. He's doing a good job with it."
Reed has similar skills as Jimmie Ward, whose $8.5 million salary for this season is fully guaranteed. Ward enters his contract year, so Reed has a chance in future seasons to take over in the jack-of-all-trades role as a younger, less-expensive option.
WR Dante Pettis
Pettis, a second-round pick from Washington, has gotten off to a good start in training camp. He has put himself in position to compete to become the No. 4 receiver at the start of the regular season due to his ability to play a number of different positions.
Pettis has a unique, deceptive route-running style. His running style also is one of the reasons he was so difficult to corral as a punt returner. He set the college football record with nine career returns for touchdowns.
"He moves differently than most guys," Garoppolo said. "He has some long limbs, long arms, long legs, and it helps him create space with defenders. He has a unique ability, I call it wiggle."
DL Jullian Taylor
Arik Armstead, who plays the 49ers' "big end" position, was expected to miss a month with a hamstring injury that he sustained on July 29. Armstead's absence has opened the door for Taylor, a seventh-round pick, to not only make the 53-man roster but to earn a significant role in the defensive-line rotation.
Taylor (6-5, 280) looks and plays bigger than his listed size. He saw action in just 15 games during an injury-plagued college career at Temple, so the exhibition season is important for his development.
"He brings an awesome mindset of physicality, violence and effort," Saleh said. "The guy's got unbelievable strain in his game. He's got a very, very long way to go."