Pretty sure MLS has been playing as inverted LB at lower level a fair few times recently too tbf
MLS Rising
This is what Arteta just said in a press conference:
on whether Mikel was involved in changing Myles Lewis-Skelly to a left-back:
When I saw him, to give him a chance and with the project that we had in the academy the moment that I saw him, the only way I could think was to change his position. I spoke to him and said I think this is where you’re going to have it, because I think it fits a lot of his qualities, the way that we play and it fits because we had necessities in the position, so we started to work on that. He got into it straight away with the personality that he has. I think it’s very obvious and now he’s doing it.
That reads to me like Arteta sees inverted fullback as MLS's best position, and the position where he can find a role at Arsenal.
https://www.arsenal.com/news/every-word-artetas-pre-aston-villa-presser-0
The new golden boy, I want to play him as a CM, bet money he is a baller there as well.
Califiori does not get back into this team, the left back position is his.
Switch him to DM. Toss Unnamed Player off the bridge and stick Timber or Cala on the left.
Keep MLS where he is. No need to disrupt his development.
BTW, I’ll be surprised if he’s not included in the next England team.
Whenever I get sad about this season I think of MLS and it puts a smile on my face
Sicario2 - Tier 1 So good!
Popped up in midfield loads and made things happen. I really hope the long term plan with MLS is to play him in midfield.
That pass at the end to Trossard 
IBL great pass but if it had a bit more on it, Tross could have slotted it in sooner and with his right foot.
Bring Back Kerrea Gilbert — he’s been under hitting quite a few passes. To be expected as he adjusts to space and timing at the pro level.
Bring Back Kerrea Gilbert
Wasn’t Tross offside though
Sicario2 - Tier 1 can't remember anymore. Lol.
Moreso than the execution was the vision to see it and disguise it the way he did, great reading the of overall play.
Yes, it's the guile that interests me so much. Always love these kind of players.
both he and Nwaneri are exactly the kinds of players we don't have enough of. Players who are able to take on opponents, but also do it with real speed. Saka and Odegaard are basically the only guy who does that consistently with security. Otherwise we are highly dependent on ball movement for beating men. So I really like both guys, and it's clear Arteta values this quality as well
Claudius both he and Nwaneri are exactly the kinds of players we don't have enough of. Players who are able to take on opponents, but also do it with real speed.
which is exactly why I'd love to see MLS playing in central midfield at some point. I think he could be a real difference maker in there - when was the last time we had a centre mid who could dribble the opposition? Santi, I think?