Confused as 3 of your four sources don't even hint at his length being even a tiny yellow flag of note....and the one that does appears as a Mayock off the cuff quote where I'd bet went off memory or just spur of the moment type expression.
So few items. The first link discussed his thin arms, some did feel he lacked the upper body structure and strength to excel right away (which was odd because others said otherwise) - different than saying his arms are too short. Unless I missed it the arms are only mentioned specifically beyond measures with this quote:
"Bakhtiari doesn't exactly have the ideal build for an Offensive Tackle as he is thin in the arms."
The second one, first bleacher one quotes:
"Bakhtiari is not the tallest of the tackle crop in 2013 at just over 6'4", but he possesses a pair of the longest arms at 34", which he uses to execute tough reach-blocks." ALSO "He has a big reach which helps immensely when "passing off" or helping teammates with defenders through zone lanes."
The third one, second bleacher one quotes:
"I don't know where they're going to play him. There's a little bit of an issue at left tackle with the Packers. He's not as tall as people would like. His arms weren't as long as you'd like, but I think he can play right tackle -- even though he has left tackle feet -- or he can play inside because he's tough."—Mike Mayock Mayock, clearly didn't look up, misread [or talking spur of moment] - his measurables being that he was 34 inches and one of the longer reaches in his class....
The fourth link:
"He uses his long arms with force and to keep defenders from latching on to his jersey."
Little confused as the discussion which prompted this was about Tackles length measurement in the arms....yet all of these sources save the one where Mayock clearly disagrees with actual measureables and I'd suspect is talking solely off the cuff or from a perspective of "sure love 34 and a half arms.."....
Here's another Mayock link discussing Bahk could be a second rounder before the draft...
https://www.nfl.com/news/path-to-the-draft-recap-mike-mayock-s-draft-risers-0ap1000000160911 "that Colorado's
David Bakhtiari is someone who could go in the second round due to his great feet. Mayock added that Bakhitiari could start at left tackle for a team someday."
