I think keeping Lallana and Welbz is beneficial for their mentoring of younger players as much as their limited game time. Lallana could become an important coach for us one day...
Or he impresses in training but is still behind Caicedo and AliMac in ability (no shame in that)...in which case it's a mistake he hasn't been rotated in sometimes to keep him match ready for this incredibly tiring run in.
For me it's the mental concentration more than the physical effort - the way we play out from the back demands 100% concentration...it must be exhausting... especially when we don't take our chances