This is the live blog for the San Francisco 49ers' preseason game against the Los Angeles Chargers. This will be updated after each drive with information and analysis.6:15 Here are five things I'll be watching closely tonight.1. How will Kyle Shanahan protect his quarterbacks?Last week, Kurtis Rourke had an outstanding performance, until the 49ers called a quarterback draw from the four-yard line. That's when Rourke ran between the tackles, got cracked from the side and broke his rib. Now, he's out, so Brock Purdy and Mac Jones will play instead. For the love of humanity, please protect them, Kyle Shanahan. Do not call any quarterback draws tonight. Don't call any zone-reads, either. In fact, just call zero quarterback runs. And then move the pocket. Have them roll out to the left and right. Don't make them easy, stationary targets behind a shaky offensive line. Make sure both quarterbacks leave the game healthy. Last season, Jones injured his PCL during the preseason, and it didn't fully recover until this offseason. Be smart.2. Will Kaelon Black have any run to run?Black has been one of the most impressive and athletic players in camp this offseason. He seems to have the juice needed to jumpstart a running game that was decidedly anemic last season. But Dominick Puni is out tonight with a concussion, and he's the only starting-caliber guard on the roster. Without him, Black and the rest of the running backs could have an extremely tough time running between the tackles. Rookie guard Carver Willis and second-year guard Connor Colby are two players to watch closely.3. Will Purdy connect downfield with De'Zhaun Stribling?Last week, Rourke connected with Stribling seven times, including once downfield for 32 yards. Stribling ran a fade route, something we rarely see 49ers wide receivers do, and Rourke hit him perfectly in stride. Can Purdy do that, too? Does he have the arm to make that throw with accurately and with enough trajectory to let Stribling run underneath it? Purdy is one of the best quarterbacks in the league when it comes to passing over the middle, but deep passes near the sideline haven't been a large part of his game in the past. Will that change this year? Mike Evans is another wide receiver who can do damage down the field near the sidelines when he has a quarterback who can put the ball where only he can get it.4. Will the 49ers generate pressure with four rushers?The 49ers had the worst pass rush in the NFL last season -- that's why they traded for Osa Odighizuwa and drafted Romello Height. Last week, Height generated zero pressures. This week, he could get to play next to Odighizuwa, which means Height could have more one-on-one matchups. Can he win some of them? Or will the 49ers have to blitz and rush five defenders to generate a pass rush this season? And if they do have to blitz, how creative and effective will they be? Last week, Raheem Morris called a couple blitzes that generated sacks for linebackers Tatum Bethune and Larry Worth.5. Can the 49ers defense break up any passes?Rookie cornerback Ephesians Prysock broke up a potential pass to Carnell Tate last week -- that was impressive. Other than him, none of the other defensive backs stood out. It would be nice to see Upton Stout or Renardo Green break up a pass. It also would be nice to see Marques Sigle show range and playmaking instincts to make a play on a pass over the middle. Because if the 49ers have to blitz to generate pressure, then these defensive backs will have to play man-to-man without safety help. That sounds risky.Add us as a preferred source on GoogleFollow