I think it's the current evolution of the team
- While the front four are all quite fluid, the starting positions if you like are Son left, Kane up front, Bale right
- With Reguilon in the side, it's clear we plan to use Reguilon/Son +center AM to create pressure on that side of the pitch (like against West Ham, opponent needs to double up on that side to avoid being destroyed), this leaves the right sided player open (against West Ham it was often Tanganga), against Burnley it was often Bale who used his passing (see Kane goal)
- Burnley despite their reputation as bus parkers do press, sometimes surprisingly high.
Lucas is the most direct/quickest of the three, hence if we broke their press high or countered he would be most likely to have an impact.
These are the decisions managers get paid for, if Lucas had an off game, the bitching of why not Dele would have been OTT
Lots of games to come, so expect to still see rotation and who knows what having Lo Celso available does to the setup.