Transport of a Brownian particle moving in a periodic potential is investigated in the presence of a symmetric unbiased external force. The viscous medium is alternately in contact with two heat reservoirs. We present the analytical expression of the net current at the quasi-steady-state limit. It is found that the competition of the asymmetric parameter of the potential with the temperature difference leads to phenomena like current reversal. The competition between the two driving factors is a necessary but not a sufficient condition for current reversals.