Southerntakeover
Hall of Famer
It's got nothing to do with depth charts.
Mackay is replacing Brown, Murray is replacing Hamill, though you can flip those two around if you like. Either way, it's 2 defenders out for 2 defenders in.
Berry is replacing Fogarty in the midfield, and this was always going to happen regardless of what was happening with the defenders.
Are depth charts another concept you don't understand?