The San Francisco 49ers and Los Angeles Chargers meet in an important preseason finale for players looking to make an impression and a spot on their team's regular-season roster. Thursday's kickoff from Levi's Stadium in Santa Clara, Calif., is set for 10 p.m. ET. San Francisco is a 4-point favorite, with the Over-Under set at 34.

A renowned sportswriter whose work appears in the New York Times and Los Angeles Times, Tierney has reported from seven Super Bowls. Tierney was all over the Patriots in the 2019 Super Bowl, enabling him to finish the season with a sparkling 63-46 record against the spread. Anyone who has followed him is WAY up.

Now, with the NFL preseason winding down, Tierney has evaluated Chargers vs. 49ers from every angle and locked in his pick. We can tell you he's leaning Over, but he's isolated a critical X-factor that has him going BIG on one side of the spread. You ABSOLUTELY need to see it before locking in any of your own.

Who wins the Chargers vs. 49ers preseason finale? And what critical X-factor makes one side of the spread hit HARD? ... Join SportsLine right now to see which side of the Chargers vs. 49ers spread you should jump on, all from the incomparable expert who went 63-46 on ATS picks last season!