You appear to have determined they have regressed based on a lack of gametime. But if the players ahead of them are doing extremely well (as they clearly are) then they aren't going to make the starting line-up, subs bench. That does not mean they have regressed, the quality bar for gametime is very high atm.
I was talking about Slattery and Vokins. I'm fully aware when Valery made his debut, he was never that great and Walker-Peters is his upgrade so Valery isn't going to play if KWP is fit.
He has been injured but now back.
As for position, Hasenhuttl quote...
"The good thing is that he can play No.10 and No.6, at No.6 he feels a bit more comfortable maybe, but on a No.10 he also can get in the box and create something."
The article is click bait. Read it and all it is is the Daily Express asking Claus Lundekvam and Dave Kitson some questions and them making a suggestion Hasenhuttl would be good for Man Utd. There is no substance to it at all.
https://www.express.co.uk/sport/football/1374816/Man-Utd-Solskjaer-Glazers-Southampton-Ralph-Hasenhuttl
Based on that article it is pretty rubbish. They have attempted to shoe horn some quotes that don't talk about Forster into an article about him possibly returning to Celtic. Really is shoddy journalism.