Finite temperature relativistic atomic structure calculations are employed to study the perturbation of energy levels and transition probabilities due to a dense plasma environment.We demonstrate that even in the framework of the hard sphere model energy level crossings are predicted.The analysis discovered not only a dependence on orbital quantum number but on spin quantum number too.Detailed calculations have been carried out for He-like aluminum and the crossing between the levels nsms(1S0) and nsmp(3P2,3P1,3P0) are studied.The dependence on plasma density and temperature is demonstrated for a wide range of parameters.