The San Francisco 49ers are coming off of a brutal first preseason game versus their former Bay Area rivals, the Las Vegas Raiders. However, fans shouldn't look too much into it. The 49ers rested the majority of their starters and prefer to see them during joint practices.

Still, the preseason performances offer a great chance for some of the 49ers unproven players to establish themselves. The 49ers have one of the strongest rosters in the NFL, so it's not easy to rise up the ranks of the depth chart, Even so, a few players on the offensive and defensive lines had impressive showings versus the Raiders. With consistency across the next practices and preseason games, those players could certainly challenge for a starting role.

One player who might have to watch out for his starting spot is defensive end, Drake Jackson. Jackson currently holds the end spot opposite Nick Bosa, but there are several players who could snag his spot or snaps including Clelin Ferrell. The former Raiders 4th overall pick in 2019 was largely regarded as a bust through his first four seasons in the NFL. After the Raiders declined his fifth-year option, he signed with the 49ers during free agency and hopes to revitalize his career with one of the best defensive lines.

Through training camp and in preseason game one, Ferrell has shown serious promise. In limited snaps versus his former team, Ferrell put up one sack and had a big run stop as well. Though Ferrell currently looks like the top contender for Jackson's position, Austin Bryant and Kerry Hyder could also challenge Jackson for snaps on the field.

The 49ers offensive line has also faced some challenges amid the start of the preseason. Though the starters didn't play, the offensive line gave up four sacks on quarterback Trey Lance and appeared shaky versus the Raiders  The 49ers offensive line was bound to take a hit when they Mike McGlinchey went to the Denver Broncos during free agency, but the 49ers can't allow so many sacks or they run the risk of another quarterback injury.

Outside of 2x All-Pro left tackle Trent Williams and center Jake Brendel, the 49ers offensive line does have some question marks. Following the departure of McGlinchey, former 49ers fifth-round pick Colton McKivitz is slated to take over the right tackle spot opposite of Williams. Though he has impressed as a pass-blocker, he has been subpar blocking for the run.

Still, the job is McKivitz's to lose according to 49ers offensive line coach Chris Foerster. “I think that knowing the job is his coming into it, and it's his job to lose kind of — all of the B guys are there to compete if it doesn't work out —, I think is also going to help build his confidence,” via Bob Heyrman of 49ers Web Zone.

McKivitz reportedly struggled in joint practices versus Raiders defensive end Maxx Crosby. Though Crosby is one of the premier pass rushers in the NFL, if McKivitz continues to struggle, it could open up the job for others.

One player who made a name for themselves in the first preseason game is undrafted free agent rookie Ilm Manning. Manning, who played tackle at Hawaii, was the best blocker versus the Raiders Sunday.

“49ers' rookie Ilm Manning was the team's top-graded pass blocker vs the Raiders. Didn't allow a pressure over 17 pass reps at left tackle — even though he's only 6-foot-2 … It was assumed he'd have to move to guard in the NFL, but he's seeing growing success at camp and in the preseason at LT — so the 49ers haven't found reason to move him yet,” via David Lombardi of The Athletic.

Manning will be one name to look out for if McKivitz or either of the guards play poorly during the preseason.