Yes, Chelsea haven't obtained a maximum of points (3 points) in their past four games in Premier League, and If you fast-forward back into their historical games records, you would find out that most of these games during December isn't always in their favor, Chelsea usually struggle or had difficulty in winning their games and getting maximum of points this period, they drew their last Premier League game against Crystal place and, lost two games, to Ipswich Town and Fulham and drew one against Everton, thereby losing 10 points in total in all these games.
Chelsea have been having difficulties lately of course this will have a bad impact on them in competing at the top of the standings with unstable performance lately they must remain focused on improving their quality again and if that does not happen then Bournemouth will steal points at home The Blues, Bournemouth are currently doing quite well in their last five matches they have not been defeated and currently Bournemouth are in 7th position where they are only 6 points behind Chelsea of course this will be an important match for both teams in maximizing points to continue to advance.
However if you look at Chelsea should be able to win this match even though they have not been good lately but they are quite good at home in the last 5 matches 4 wins and 1 loss, and my bet for this match is for home because overall Chelsea can win this match.