They lost Trevor Ariza to the Suns, they lost Luc Mbah a Moute to the Clippers, and their only replacement will either come in the form of Ryan Anderson, PJ Tucker, or a 34 year-old Carmelo Anthony who shot a career low 40% last season.
And now, to make matters even worse, they are in danger of severing their relationship with Clint Capela, a guy crucial to what the Rockets did last season. His defense around the rim is priceless and provides enough inside scoring/rebounding to make the team shooters' (Harden, Gordon, Paul, etc.) jobs a whole lot easier.
His value to the team is vital and is likely why he is currently commanding a 4 year, $100m contract. The Rockets, however, are reportedly only offering him a 4 year deal near the $60 million range (via ESPN.com's Tim MacMahon.) To complicate the situation further, Capela is a restricted free-agent and the market is rather limited anyway, with the majority of teams not even having enough money to pay him what he wants.
This will likely lead to a stand-off that could extend well beyond the summer. So if both sides don't find a middle ground soon, their relationship could sour beyond repair.