Callahan may be one of the best OL coaches in the business and it would be fantastic if we could get him, but there are some pretty damn good OL coaches available.
Marc Columbo - coached that fantastic O-Line of the Cowboys this past season with Jason Garrett. Smith, Collins, Frederick, Martin...yeah the talent was there, but they had to be coached. According to Football Outsiders, the Cowboys offensive line was near the top in nearly all their offensive line metrics:
Second in adjusted line yards
Sixth in running back yards
Second in power rank
First in stuffed rank
First in second level rank
Second in pass protection
Second in sacks allowed
Second in adjusted sack rate
Even for you PFF guys, Pro Football Focus graded the Cowboys offensive line high-ranking fourth overall. The unit received the third best run blocking grade and the fifth best pass blocking grade.
Harry Hiestand - coached Ronnie Stanley, Quenton Nelson, Zack Martin, Mike McGlinchey Jr., etc at Notre Dame. Hiestand built a line that won the 2017 Joe Moore Award for the nation’s best line.
James Campen - Campen helped six Packers offensive linemen earn Pro Bowl recognition from 2010 to 2018, the only team in the league to have six different members of the offensive line selected over that span. He helped develop David Bakhtiari from a fourth round pick into one of the best, if not the best, LT in the NFL.
“Coach Campen is a great football coach and he will be missed in our room. He’s been my coach since I was a rookie and has been a huge reason why I am the player I am today — not only because of his instruction but because of the trust and freedom he lets his guys play with.
“I am very grateful for how he stuck with me and kept believing in me through all the injuries. He gave me the confidence to come back from two ACL surgeries and play at a high level.” - Bryan Bulaga
And yeah, Bulaga was a first rounder, but look at some of the other guys he helped develop. Josh Sitton (fourth round, 2008), T.J. Lang (fourth round, 2009), David Bakhtiari (fourth round, 2013), Linsley (fifth round, 2014)...