Our staff writers break down the San Francisco 49ers third preseason matchup, a road game against the Minnesota Vikings.

Let's dive into the keys to the game in this "Four Downs" preview of the 49ers exhibition contest, presented by SunPower.1st Down:Which 49ers player needs to perform well?@JoeFann: Pierre Garçon

Hoyer's job is by no means in danger, but that doesn't mean it isn't important for the first-team offense to get going. The 49ers starters had some promising moments last week against the Denver Broncos, but three straight drives ended with a turnover. Hoyer's stat line wasn't awful, 8-of-11 passing for 89 yards and one interception, but it would be nice to see some points in Sunday's "dress rehearsal". The first-team offfense has scored just three points through two preseason games, and that field goal came after a Rashard Robinson interception gave the 49ers great field position. The Vikings have a fantastic defense, so any offensive success would provide great momentum into the regular season.

@KeianaMartinTV: C.J. Beathard

Head Coach Kyle Shanahan said this week that he's seen Matt Barkley perform on an NFL level, and he's taking the 49ers third preseason game as an extended look at C.J. Beathard. For the second straight week, Beathard will receive the call as the backup to Brian Hoyer on Sunday against the Vikings. He's been consistent over the first two preseason games completing 14-of-23 passes for 211 yards, three touchdowns and no interceptions. Despite not playing against defensive starters in the preseason, he's shown poise and accuracy in the pocket. He ranks third in the league with a 135.4 passer rating under pressure according to Pro Football Focus. He has an opportunity to secure the backup quarterback role ahead of Barkley. 2nd Down: What position group are you watching closest?

@JoeFann: Defensive line

In my opinion, the 49ers defensive front is the deepest spot on the roster. There will be players that get cut who sign with other NFL teams. I'd imagine with cuts less than a week away, some anxiety is starting to fill that meeting room. The addition of Sen'Derrick Marks only muddies those waters when trying to predict who will be on San Francisco's 53-man roster. Chris Jones and Quinton Dial are two names to watch Sunday night against the Vikings.

**@KeianaMartinTV**: Running back

San Francisco is challenged with narrowing down six running backs who are all vying for roster spots. Shanahan suggested the possibility of keeping as little as two and as many as four backs on the roster. Pierre Garçon has started both of the 49ers preseason games. Veteran Tim Hightower got his first run last week against the Denver Broncos. Then there's fourth-round draft pick Joe Williams, who Shanahan was keen on drafting. That leaves third-year back Kapri Bibbs, Raheem Mostert and undrafted rookie Matt Breida, who is coming off of a strong training camp. Despite San Francisco's first-half struggles in the run game, there's undeniable talent across the board. 3rd Down: What is the key statistic?

@JoeFann: Halftime score

As John Lynch put it, Sunday's game is the best measuring stick that the 49ers will get before Week 1 against the Carolina Panthers. Both teams are expected to play their starters for at least the first half. There's a chance that 49ers starters play into the third quarter, but a halftime lead would likely have Kyle Shanahan deciding that he's seen enough.

**@KeianaMartinTV**: Zero turnovers

San Francisco was haunted by an overwhelming five turnovers in last Saturday's game against the Broncos. General manager John Lynch said on KNBR last week that he'd be very surprised if that same result continues going forward. Eliminating turnovers will be pivotal on Sunday.4th Down: What is your bold prediction?

@JoeFann: Carlos Hyde finds the end zone

My prediction is admittedly far less bold than Keiana's, but I'm going to double down after shooting an airball on this one last week. Hyde has had a slow start to the preseason. He had eight carries for 26 yards against the Broncos, but most of those yards came in the second quarter against second- and third-stringers. It would be a great sign to see Hyde get going against the Vikings.

**@KeianaMartinTV**:100 yards 2 touchdowns from Aldrick Robinson

Veteran receiver Aldrick Robinson is looking comfortable in the 49ers offense. Robinson has three receptions for 122 yards in limited playing time this preseason. His longest reception came on a 63-yard catch-and-run from quarterback Matt Barkley in the 49ers preseason opener against the Kansas City Chiefs. Last week, the Vikings defense gave up six receptions of more than 20 yards. With the opportunity for extra playing time on Sunday, I'm predicting Robinson to break 100 yards this week and score twice.