Since the end of USC's 2020 football season, the Trojans have lost six players to the NFL draft and several others to the NCAA transfer portal.

Such attrition is common this time of year across college football -- now more so than ever.

But the USC depth chart had an easier offseason last year with only two players drafted and no projected starters transferring out (though quarterback JT Daniels was certainly a starter-caliber talent who proved his worth this year at Georgia).

The toll is a little more taxing this offseason. We rank the most damaging departures and our best guess at how USC fills the voids.

Alijah Vera-Tucker was terrific for USC as the starting left guard in 2019 and was even more valuable in 2020 as the starting left tackle. He has a good chance to be the Trojans' second-straight first-round NFL draft pick from the offensive line (following LT Austin Jackson last year).

And he leaves a gaping void behind.

USC was already so thin on tackles entering this past season that it had to move both of its starting guards outside in Vera-Tucker (who mostly excelled in the role, save for some struggles in the Pac-12 championship game) and Jalen McKenzie (who struggled with the transition).

USC only got three of its reserves any meaningful playing time this year, and all on the interior -- redshirt sophomore Justin Dedich at center and freshmen Courtland Ford and Jonah Monheim at the guard spots for one game.

So how do the Trojans replace Vera-Tucker at left tackle?

RELATED: More on Alijah Vera-Tucker's NFL draft decision

Our best guess: A transfer TBD

USC will again try scouring the transfer portal for immediate help at the position. The Trojans landed Tennessee transfer Drew Richmond heading into the 2019 season and he became their starting right tackle. They tried and missed on a couple grad transfer targets last spring/summer. And they'll evaluate all options in the portal yet again. There are no known leads at this time and USC will take a pragmatic approach -- it's not just about adding a player, it's about adding a clear impact offensive tackle, and those are hard to find in the portal at this position. But the post-spring portal rush is another opportunity to evaluate the options.

If the roster remains as it is now and there is no incoming transfer to fill the void, the spotlight would be on Ford, Monheim and fellow 2020 freshman Casey Collier to show quick development during spring and fall camp. While Ford and Monheim both got playing time at guard this season, Monheim worked as the backup right tackle all fall and both players are viewed as versatile enough to play on the outside. Collier sure looks the part at 6-foot-7, 290 pounds, but with media unable to watch any practice this year, it's more of a mystery where he is at in his development. Our intel is that the coaching staff is very high on his upside, though.

We'll also introduce a wildcard to the equation in incoming 4-star Rivals250 OT Mason Murphy. Murphy is an impressive prospect with plus agility and good size at 6-foot-6, 290 pounds. He also boasts a tireless work ethic. His obstacle is not only being a true freshman, but a true freshman who doesn't arrive until the summer. But expect him to come in with the mentality of competing for a job right away.

That's a long way of saying we don't have a clear answer for this position yet -- and the USC staff likely doesn't either.

The Trojans didn't just lose a starting safety when consensus All-American Talanoa Hufanga announced he was leaving for the NFL -- he was so much more to this defense.

The way he was used overlapped with other roles at times and he was even the outright middle linebacker one game while filling injury voids. His instinctual play-making abilities, versatility and general leadership are the real loss for the Trojans.

But in terms of simply finding another starting safety -- not necessarily another Talanoa Hufanga -- we have some thoughts.

RELATED: More on Talanoa Hufanga's NFL draft decision

Our best guess: Incoming transfer Xavion Alford

USC had thin depth at the safety position in 2020, but that is changing quickly with Alford -- a 4-star Rivals250 prospect from the 2020 class -- transferring in from Texas this winter, and 4-star prospects Calen Bullock, Xamarion Gordon and Anthony Beavers arriving as early enrollees.

With Greg Johnson and Max Williams used primarily in the nickel safety role (USC views the nickel as an extra safety rather than cornerback), the returning options at the safety position are redshirt sophomore Chase Williams, sophomore Briton Allen and redshirt freshman Kaulana Makaula. (With the NCAA giving every player a free year in 2020 due to the pandemic, eligibility years essentially remains the same for 2021). Graduate transfer walk-on Micah Croom was actually the true backup to Hufanga this season on the depth chart, but he barely saw any snaps on defense and it's unclear if he'll choose to return for another year.

Chase Williams will certainly get a long look at the position. He played 124 defensive snaps in 2020, per PFF, and 443 in 2019. The results have been mixed in those opportunities, though.

We pick Alford as the favorite because he was a priority recruit for USC safeties coach Craig Naivar at Texas, and Naivar then quickly landed him again here after Alford hit the transfer portal. The former top prospect expects he's coming in to compete for a job, and he might be the most talented of all the options who will be in the mix here.