Chargers vs. 49ers: 5 things to watch in San Francisco’s preseason finale

The San Francisco 49ers wrap up their final week of action during the 2019 preseason, hosting the Los Angeles Chargers on Thursday night. While this is a dull exhibition game for most, there are still important things to watch.

For the casual San Francisco 49ers fan, Week 4 of the preseason isn't exactly must-watch football. Starters and immediate reserves won't see any action, and all the players on the field between the Niners and visiting Los Angeles Chargers are arguably vying for one of only five or six spots on each respective roster.

That doesn't mean the game lacks importance, though.

Those final spots are still open. And with NFL rosters around the league set to be trimmed from 90 players down to 53 on Saturday, Aug. 31, Thursday's game could easily wind up being the last pro-level action many a player ever sees in his career.

There is more to last-ditch hopes for head coach Kyle Shanahan's squad, however. Let's dive into some of the notable storylines and topics fans should pay attention to during the game itself.

Offensive Line Depth

The 49ers have their starting cast of offensive linemen set for the regular season. It's highly unlikely center Weston Richburg sees any field time, despite being activated off the PUP list earlier. But his injury painted a pretty crucial point for Shanahan: O-line depth.

Reserve interior lineman Ben Garland received most of the first-team reps at center in Richburg's stead. While this bodes well for Garland's roster chances, one could argue some inconsistent play this preseason still squarely places him on the roster bubble. Same goes for guards Ross Reynolds, Joshua Garnett and Najee Toran. Nothing different for swing-tackle candidates, Sam Young and Justin Skule.

There are other names in the mix, too.

San Francisco will get four full quarters of reserve O-line action, which could be instrumental in determining how this unit's depth pans out in 2019.

Will Dante Pettis See the Field?

There are a number of viewpoints going around about second-year wide receiver Dante Pettis. Pettis was on the field in the fourth quarter during the 49ers' Week 3 preseason bout against the Kansas City Chiefs last Saturday, which was somewhat odd. Shanahan later told reporters Pettis was "still trying to earn a role" on the team.

Shanahan never said, however, Pettis was in danger of losing a roster spot.

It should be clear the head coach is trying to push Pettis even more, especially after Shanahan later admitted such.

Whether or not this proverbial "fire lighting" involves Pettis playing Thursday night could be something worth adding to the discussion.

Running Back Jeff Wilson

KNBR 680's Greg Papa pointed out something interesting Thursday afternoon, trying to read into what could happen with second-year running back Jeff Wilson in regards to his chances making San Francisco's 53-man roster.

If Wilson plays -- and that wouldn't be shocking -- he'd have this one final shot to prove he belongs on the Niners in 2019. Regardless of the context and situation, Wilson's efforts would be important. But Papa also suggested Wilson not playing could possibly mean the running back has already done enough to make the cut.

Especially with recent news fellow running back Jerick McKinnon suffered yet another setback in his ACL recovery and still has an unknown future for the regular season.

If Wilson doesn't play, Papa could be right. But if Wilson sees the field, look for an exceptionally strong and desperate performance.

Kendrick Bourne vs. Jordan Matthews

Shanahan could end up keeping only six wide receivers on his 53-man roster. Perhaps he keeps seven, even eight isn't completely out of the question. But just going through the names all but locked in -- Pettis, Deebo Samuel, Jalen Hurd, Trent Taylor and Marquise Goodwin -- there's room for one, maybe two more.

Second-year receiver Richie James has been outstanding this preseason. Combining his special teams abilities, he likely makes the cut. So there could only be one left, and it falls between the veteran, Jordan Matthews, and the third-year pro, Kendrick Bourne.

Bourne is still vying to reach his ceiling. And while he has had some solid moments this training camp and preseason, he's also had some questionable issues, too, namely in the drops department. A major drop in Denver against the Broncos during Week 2 of the preseason could stand out.

Matthews, meanwhile, is far more proven. But he's also pretty much hit his ceiling.

Both are highly likely to see the field Thursday night. Whoever performs better surely stands a much better chance to get the regular-season call.

C.J. Beathard's Last Chance

Third-year quarterback C.J. Beathard didn't see the field in Kansas City. The Niners' second-half efforts under center were almost entirely handled by Beathard's primary competitor in the team's backup competition, Nick Mullens, who gave way to undrafted rookie Wilton Speight for San Francisco's final offensive drive.

Beathard will likely see the vast majority of play against the Chargers, however, perhaps spilling over into the second half. And while Shanahan has made suggestions the team could keep three quarterbacks on its regular-season roster, one has to wonder if those remarks were mere "coachspeak" instead of actual fact.

There's the possibility Shanahan indeed keeps both, of course. But given the question marks elsewhere on the roster, the smarter bet would be just one, between Beathard and Mullens, backing up the starter Jimmy Garoppolo.

Tonight's contest could be the last opportunity Beathard gets to impress Shanahan and the coaching staff, at least making the competition with Mullens a bit more interesting.

The 49ers and Chargers kick off on Monday, Aug. 29 at 10 p.m. ET.