It's hard to make it into the Pro Football Hall of Fame in general, but it may be even harder to do it when you're an offensive lineman. All that most people have to go off of is reputation and so to be considered a lock to make the Hall as a left tackle before your career is even over is an even bigger accomplishment. Think about this: The only tackles to be elected from the last 15 years are Orlando Pace, Walter Jones, Willie Roaf, and Jonathan Ogden.
Soon(ish) they'll be joined by the Eagles' Jason Peters, an eight-time Pro Bowl, six-time All-Pro tackle, which seems all well and not worth digging into if you don't know much about Peters, but consider where those tackles came from:
Pace was the first overall pick, Roaf went eighth overall, Jones went sixth overall, and Ogden went fourth overall. Joe Thomas (third overall) is also a lock to make the Hall of Fame.
Peters wasn't drafted.
As a freshman at Arkansas, Peters was a reserve defensive lineman who had been recruited to play defensive tackle. As you may have guessed, he was moved to offense by his sophomore season but not to play offensive tackle; Peters was moved to tight end and he caught 58 passes over the next two years.
(Here he is (at 305 pounds) catching a two-point conversion to force a seventh overtime against Ole Miss.)
However, when he entered into the 2004 NFL Draft, Peters was both "not a very good tight end prospect" nor "an offensive line prospect with any experience of note." He was only a body, but what a body he was: 6'4, 328 pounds, 4.93 in the forty-yard dash, 31.5 inch vertical, 9'7 broad jump, 25 reps on the bench, and 1.89 in the 10-yard split.
That's faster than any offensive tackle in the draft this year, the closest being Indiana's Jason Spriggs, who ran a 4.94 but at 301 pounds. It's the same vertical leap as the 301-pound Spriggs and the only tackle to jump higher was the 324-pound Germain Ifedi, who ran the 40 in 5.27 seconds. Only four tackles did more than 25 reps this year on the bench, and the 9'7 broad would tie Spriggs for the longest at the combine.
In other words, Jason Peters is one of those freak-of-nature athletes that if he were in the draft today, Pete Carroll would never let him slip past the fifth round.
There simply is no comp in the draft this year to Peters (nor are there during most decades) but Spriggs is the closest thing, followed by Ifedi. If either are available at 26, there's a decent chance that it would take another prospect that the organization is completely enamored with for them to take a pass on one of those tackles. There's also the possibility that Carroll and John Schneider think that Spriggs might fall to the early second round because of his technique issues, but that has never been something that the Seahawks have shied away from under this regime. If so, then once again they could trade down and take their chances that Spriggs or Ifedi are available at 35 or something while picking up another pick or two.
However, they may also feel comfortable taking that risk because they feel like they already have an elite left tackle prospect on the roster and even if they do take Spriggs or Ifedi (and if not, they'll certainly take a tackle in either round two or three or both), left tackle might not be their job to win; Spriggs could immediately be named a right tackle simply because Garry Gilliam could be a better left tackle on the rise than we've given him credit for.
Why aren't we giving him any credit? Well, because he wasn't drafted, of course.
In 2014, Gilliam decided to leave Penn State with a year of eligibility left because he didn't want to go through a second coaching change after Bill O'Brien signed with the Houston Texans. He knew he was a taking a risk though because there was basically no chance that a team was going to draft a tackle who was recruited as a defensive lineman and then moved to tight end.
We had already seen the writing on that wall 10 years earlier.
But Gilliam changed his diet and exercise plan in order to add lean muscle and maintain a 310-pound frame without losing his athleticism. At his pro day, which was only hindered by the losses of O'Brien and the coaching staff that was supposed to help him train for this moment, Gilliam ran a 5.03, had a 9'5 broad jump, a 35 inch vertical leap, did 19 reps on the bench, and a 1.68 in the 10-yard split.
He wasn't as fast as Peters in the 40 (few at that size ever will be), but he was faster in the 10, the 20, had a higher vertical leap (2.5 inches higher than any tackle at the combine this year), and an elite broad jump. His 3-cone time of 7.59 would've ranked third among all tackles at the combine this year too.
These are the reasons that Gilliam is in Seattle and why he started 16 games at right tackle in 2015, five years after tearing his ACL, four years after missing the 2011 season, and three years after being a tight end at Penn State. Gilliam started just four games at offensive tackle during his college career, but he's now an NFL starter and arguably the best one on the Seahawks offensive line last year.
So why can't he be the team's left tackle of the future and possibly a very good one?
In 2004, nobody thought anything of Jason Peters. Not only did he go undrafted but he was cut by the team that signed him, the Buffalo Bills, before being brought back onto the practice squad. Anyone could have had this future Hall of Fame tackle. Just like Gilliam, he made one start during his first season.
In year two, he became the regular for the Bills at right tackle.
In year three, he moved to left tackle.
In year four, he started a run of eight straight seasons of making the Pro Bowl (not including the one year he missed due to injury.)
As of now, Gilliam and Peters are basically on the exact same trajectory. That has little bearing on the future of Gilliam, but it makes for a great example of how ignorant it can be to assume the worst of a player's future simply because he has a mysterious and unusual past. It would be much worse if Gilliam was a bad or overrated offensive tackle in college (take Ronnie Stanley for example) but Gilliam only started learning how to play tackle at this weight two years ago. This isn't a player who has been playing the position for seven or eight years, like you'd expect from a guy going into his third NFL season, this is a guy who may only be scratching the surface of what he can do.
And for that reason, I have as much reason to believe that Gilliam will become a great NFL left tackle as I do that he will be relegated to being an average right tackle for the rest of his career. It's not like I'm saying he's going to be a first ballot Hall of Famer or anything, but I will say this:
He's a second-ballot Hall of Famer.