how was he in pass defense?
Not sure, frankly. I don’t have access to that stuff.
But fwiw here’s a couple of PFF comments on Barron from duringg the season:
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OCT 23, 2017
https://www.profootballfocus.com/news/pro-nfl-week-7-inside-linebacker-spotlight
PFF Grade: 83.7
Run Stop Percentage: 11.5 percent
In his first full season at the 3-4 inside linebacker position, the former safety-turned-linebacker is proving to be an integral part of Wade Phillips’ defense in 2017. Through seven games of the season, Barron has played a total of 165 snaps against the run and has produced 27 tackles and 19 stops. Barron moved to linebacker full-time in 2016, and he has produced 52 total run stops since, the fourth-most among off-ball linebackers in that span.
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Nov 13, 2017
https://www.turfshowtimes.com/2017/11/13/16644652/los-angeles-rams-houston-texans-recap-grades-pro-football-focus-game-notes-week-10
Linebacker Mark Barron added his third interception of the season with the Texans threatening to score and with the defense backed up in their red zone. His three interceptions on the year are now two less than he had in his previous five seasons combined, and he started his career as a safety. Adding two defensive stops to his stat line helped generate an overall game grade of 83.1, 13th highest among linebackers in Week 10. With his two defensive stops on Sunday, Barron brings his season total to 29, which is 10th most among inside linebackers, with 22 of them coming in the run game on 210 run snaps. His 22 in the run game rank seventh among 53 inside linebackers, with the 10th best run stop percentage with a 10.5. Barron is absolutely flourishing in Wade Phillips’ 3-4 scheme he brought with him to Los Angeles, with his 83.0 overall grade through 10 weeks reflecting that, after not grading above 77.8 in any season of his career.