The San Francisco 49ers will play more starters in the second preseason game. However, those players will mostly just shake the rust off. The preseason is still about the depth battles and players who can set themselves up for breakout seasons. Who on offense do 49ers fans need to watch?5 Must-Watch Offensive Players in Preseason Week 2 Kaelon Black The rookie running back had an adductor injury and missed the preseason opener. However, he returned and might have gotten just enough work to be thrown into the mix in the preseason. The team needs him. Christian McCaffrey is unlikely to play, Jordan James has broken ribs, and Isaac Guerendo is on the PUP. They might need Black to take legitimate carries in Week 1. He better get acclimated to the NFL in the preseason. Demarcus Robinson Robinson has been the biggest winner of training camp. First, he has been the healthiest receiver, which has given him the most opportunity. He has taken advantage, though. Last week, he was rested with the starters. Still, De’Zhaun Stribling played like a starter in his debut.Does Robinson still get starter treatment, or does the rookie start to eat into his time with the first-string offense?IMAGN IMAGES via Reuters ConnectHayden Rucci Tight end Hayden Rucci was quietly a winner from the preseason opener when he got on the field for the second drive of the game in the preseason opener. He is a blocking threat coming from Miami, so he has experience with Mike McDaniel, who runs a similar offense. With George Kittle out, Rucci could find a way to slip onto the 53-man roster with two more solid weeks.Carver Willis Willis played with the backups last week. He was up and down, but it was enough for the team to give him work with the starters this week. Considering he has spent most of the practice time with the first team, he should start in the second preseason game. How has he progressed in his few weeks at left guard?Austen Pleasants Trent Williams will not play in the preseason, and Vederian Lowe is still hurt. So, Pleasants, who started in Week 18 last year, will get a chance to protect Brock Purdy once again. With rookie Enrique Cruz and Lowe being a free-agent signing with some money committed to him, Pleasants has the least invested in him. Can he find a way to beat out both and win the backup left tackle job?Add us as a preferred source on GoogleFollow