Editor’s note: This is the sixth installment of Dane Brugler’s 2027 NFL Draft Summer Scouting series. Previous ranking: Wide receivers | Defensive tackles | Running backs | Linebackers | CornerbacksAlthough it isn’t quite the “three yards and a cloud of dust” conference anymore, the Big Ten dominated as I stacked the interior offensive linemen this summer. I wouldn’t call any of the prospects there a lock to land in the first round, but more than a few look like immediate starters in the NFL.(Notes: An asterisk represents draft-eligible underclassmen. Heights and weights are what NFL teams currently have on file for each player, per league sources.)1. Kade Pieper, Iowa (6-4, 298)*Best traits: Run-game athleticism and intensityIt isn’t always picture perfect, but Pieper offers rare athletic range and you know exactly what you are getting from a competitive temperament standpoint. He flies out of his stance with bad intentions to reach the second level or execute in space. He is always looking to run his feet at contact and finish defenders on the ground.I don’t care which tape you watch from Iowa’s 2025 season — Pieper has numerous examples on each of both his fluid athleticism and competitive demeanor, specifically in the run game.Kade Pieper highlights Dane BruglerMust improve: Matching up versus powerPieper isn’t as undersized as former Hawkeyes Tyler Linderbaum or Logan Jones, but he doesn’t have ideal size by NFL standards, which will show at times against power. There isn’t much he can do about his measurements, but Pieper needs to continue honing the ways he uses leverage and compensates when facing defenders who are bigger and more explosive.2027 NFL Draft outlookIowa had three offensive linemen drafted in the top 150 this past April, but an argument could be made that its two other 2025 starters (Pieper and Trevor Lauck) are even better NFL prospects. A two-time hay bale tossing champion, Pieper became a starter last season and immediately stood out on a veteran offensive line, earning All-Big Ten honors at right guard.Pieper moved from guard to center during 2026 spring practices, so he will look to follow in the footsteps of Linderbaum and Jones by becoming a top-60 pick. He enters the season as my top-ranked center.2. Greg Johnson, Minnesota (6-7, 327)Best traits: Processing and anchorThere is a lot to like about Johnson — he moves well with a competitive streak and the play strength to battle in the trenches. But I came away most impressed with his quick processor and ability to put down roots in pass protection. For a relatively tall interior lineman, Johnson reads quickly and uses bend and balance to establish (and reestablish) his base.Oregon had one of the top defensive lines in college football last season, but Johnson used his smarts, leverage and base strength to anchor down.Greg Johnson vs. OregonDane BruglerMust improve: Hand exchange consistencyWhen Johnson had a negative rep on tape, it was usually because of a mistimed strike or his hands landing outside the frame of the defender. The next step in his development is to avoid disadvantages by using more consistent hand placement to match his hips and feet.2027 NFL Draft outlookJohnson is one of the few players in college football with experience at all five spots on the offensive line. After starting at center as a sophomore in 2024, he moved to left guard last season, plus filled in at left and right tackle when needed, earning All-Big Ten honors.At a verified 6-feet-6 1/2 inches and 327 pounds, with 33-inch arms and an 81-inch wingspan, Johnson plays with the size, toughness and intelligence coveted at the next level. If he shows continued technical refinement with his hand strikes as a senior, he will be in the conversation to be one of the first interior lineman drafted.3. Anthonie Knapp, Notre Dame (6-4, 300)*Best trait: Nasty blocking demeanorBlocking through the echo of the whistle sounds cliché, but it is more of a mantra for Knapp. In both gap and zone looks, the Georgia native is quick into his run blocks and has the heavy hands to be a people-mover. His body control and core power are above average, but his competitive toughness makes him an ass kicker.Knapp was throwing bodies all over the place on last year’s Navy tape:Anthonie Knapp vs. NavyDane BruglerMust improve: Recovery athleticismKnapp is a good athlete for an offensive lineman, which shows in his setup and how he runs his feet at contact. However, his ability to mirror in space and react quickly to twitchy pass rushers can be an adventure, which is partly why a transition from tackle to guard makes sense. Given his average length, a move inside should reduce his lunging tendencies and improve his recovery skills.2027 NFL Draft outlookUndersized in high school, Knapp wasn’t a sky-high recruit (No. 26 offensive tackle in the 2024 class). Georgia was his “dream school” while growing up near Athens, but the Bulldogs never offered. Despite being unheralded when he arrived in South Bend, Knapp went to work and surprised many by earning the starting left tackle job from day one of the 2024 season.Over two years with the Irish, Knapp has only played left tackle (27 starts) but is expected to move to guard for the 2026 season, which is the best plan for both the short and long term. Although he still needs to put strong play on tape at his new position, Knapp has the core strength and competitive toughness that should translate well and make him a candidate to potentially enter the 2027 NFL Draft.4. Austin Siereveld, Ohio State (6-5, 325)*Best trait: Finishing mentalitySiereveld was the most consistent offensive lineman on Ohio State’s 2025 tape. He shows a good feel for angles to protect the pocket or wall off defenders from run lanes. For a 325-pounder, he offers range as a blocker, especially on pin-pull concepts. However, I think my favorite part of his tape is his finishing mentality.Austin SiereveldDane BruglerMust improve: Reactions versus inside countersSiereveld more than held his own on an island in pass protection in 2025, not allowing a sack at left tackle. However, his feet did get heavy at times, especially when attempting to quickly adjust to inside counters. Veteran pass rusher Akheem Mesidor was able to take advantage of that a few times on the Miami tape.2027 NFL Draft outlookThe Buckeyes were able to fend off Alabama, Notre Dame and others to keep Siereveld in his home state. After redshirting in 2023, he bounced between both guard spots on Ohio State’s national championship-winning squad as a freshman. Last season, Siereveld moved to left tackle and filled a major need.With four returning, quality starters, Ohio State’s offensive line should be a strength — and Siereveld might be the best of the group (although Luke Montgomery has a case). The main question: Where will he play? Siereveld started all 14 games at left tackle last season and earned All-Big Ten honors, but he is built more like a guard and is a potential All-American with a move inside. Will another left tackle (Ian Moore?) emerge for the Buckeyes or will the coaching staff be forced to keep Siereveld (and his steady play) on the outside?5. Carter Smith, Indiana (6-5, 307)Best trait: Balance through engagementQuick out of his stance in pass pro, Smith stays square to defenders and maintains his balance at contact to absorb force. His footwork stands out, not only because of his movement skills, but also in his ability to settle post-contact and stay centered to his target.Smith processes well and shows a natural feel for different types of blocks. But the common theme on tape is his balance through engagement.Carter Smith highlightsDane BruglerMust improve: Protecting versus lengthSmith has a strong frame and usually plays with good body position, but average arm length (verified 33 1/4 inches) leaves him at a disadvantage at times. He can struggle against rushers who get on his edges, which leaves him at a disadvantage in his attempts to recover, especially in space.2027 NFL Draft outlookThe 2026 version of Indiana will look very different from last year’s national champions, but there are a few important holdovers, including Smith at left tackle. The Ohio native bypassed a likely Day 2 draft slot to return to Bloomington for his fifth season, giving the Hoosiers an essential veteran presence on offense.A college left tackle, Smith has the skill set to survive outside in the NFL, but he is ideally suited for a move inside to guard or center. He plays with a level of toughness and savvy that will allow him to compete for starting reps very early in his career.Top 20 senior interior offensive line prospects:1. Johnson