Chelsea surprisingly lost to Southampton 0-2 in the last league game at home, adding to two defeats without scoring a goal.
On the other hand, Burnley have got wins or defeats alternatively in the last 4 away games, so they are in unstable form now.
AH market provided home team a -1.50 line for this game.
Since the Blues are going down hill in form, bookmakers might have overestimated the home side.
Therefore, the Blues are not expected to beat the odds.