With one key piece of the offense returning, another has officially walked out the door.

UCLA football left tackle Sean Rhyan has decided to declare for the 2022 NFL Draft, he announced on Instagram on Monday. Rhyan had two years of eligibility remaining.

Rhyan's decision came just over an hour after quarterback Dorian Thompson-Robinson announced he would be returning to Westwood for his super senior year in 2022. The Bruins' signal-caller will therefore be part of a very different offense moving forward, with Rhyan, right tackle Alec Anderson, receiver Kyle Philips and tight end Greg Dulcich all leaving for the pros.

Running back Brittain Brown and left guard Paul Grattan exhausted their collegiate eligibility this past fall, so they will be departing as well. Depending on what running back Zach Charbonnet and receiver Chase Cota decide to do, UCLA could end up having to replace eight of the 11 starters on offense this offseason now that Rhyan has made his intentions clear.

Rhyan's departure alongside Anderson and Grattan shakes the offensive line up enough as it is, but offensive coordinator and offensive line coach Justin Frye is reportedly being poached by Ohio State as well.

Frye leaving the program may have impacted Rhyan's ultimate decision, and now UCLA has to find replacements for both of them, as well as Anderson and Grattan.

Rising sophomore Garrett DiGiorgio is the only other true tackle on the roster with any game experience, as he started at right tackle against Colorado on Nov. 13 with Anderson injured. The only offensive lineman that the Bruins signed as part of their 2022 recruiting class is local tackle Sam Yoon, while Josh Carlin, Patrick Selna and Thomas Cole will likely be competing for a starting job as well.

Replacing Rhyan won't be as simple as a plug-and-play, considering the high levels he reached over the past three seasons.

Rhyan was the top-ranked prospect in coach Chip Kelly's first full recruiting class, and the former four-star remains the highest-rated signee since Kelly arrived in 2018. The 6-foot-5, 320-pound lineman became UCLA's starting left tackle on day one, and he earned Freshman All-American honors from USA Today, The Athletic, Pro Football Focus and the FWAA in 2019.

While Rhyan didn't earn any hardware starting all seven games for the Bruins in 2020, he still improved and rode that momentum into 2021. Rhyan was on the All-Pac-12 First Team as a junior this past fall, and between the 19 games he started in 2020 and 2021, Rhyan took 703 snaps in pass protection and allowed just one sack.

UCLA's offensive line paved the way for Joshua Kelly and Zach Charbonnet to post 1,000-yard seasons in 2019 and 2021, and Demetric Felton was on pace to do the same in 2020 if it weren't for the COVID-shortened schedule. 

In an exclusive preseason interview with Sports Illustrated's NFL Draft Bible president Zack Patraw, the draft insider pegged Rhyan as a potential first round pick should he prove more aggressive throughout the season.

"He's very explosive in his sets, aims his punches very well, engages blocks with good timing, he's rarely lunging at blocks," Patraw said. "He's a guy that's gonna be NFL-ready for you. He's athletic and well-rounded."

Rhyan has more commonly appeared in the second and third rounds of recent mock drafts, though. The NFL Draft Bible has him ranked as the No. 5 tackle and No. 53 overall prospect in this year's class – giving him a current value grade of "Average Starter" and a potential value grade of "Solid Starter" – while PFF has him at No. 13 and No. 81, respectively.

The last time UCLA had its starting left tackle declare early was Kolton Miller back in 2018, and he ended up getting picked No. 15 overall by the Oakland Raiders and starting 63 of their next 65 games.

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