Very valid topic. Played with 3 left backs in back 4 (Robertson, Tierney, Mulgrew) a lot last campaign.
Interesting to read thoughts on this thread about giving young players a chance or not.
Thoughts on this issue here: https://thefootballblether.com/2017/12/02/will-the-scottish-centre-halves-please-stand-up-please-stand-up/