It makes perfect sense, it is difficult to maintain the top four position without an overhaul in the main squad. The negative results obtained from Arsenal in a friendly match made anyone skeptical of Chelsea strength, especially Chelsea movement was very slow in the transfer market. The Premier League, which is inhabited by many big clubs, always provides high competition for the title, without a team reshuffle in the transfer window it is very difficult to compete at the top.
Chelsea is really inactive in the transfer market this season. The best player are been bought by most actively engaging clubs and Chelsea is really losing out. If they fail to sign more players, next season might be disastrous because they might not have enough players on the bench or to replace injured ones. Their players might be overworked which can lead to drop in performance. But the club still have time to turn the tide to their favor because the transfer market is still open and they can still clinch the services of some quality players.