  We have demonstrated the effect of pressure on magnetization jump and its
associated magnetostriction in Eu$_{0.58}$Sr$_{0.42}$MnO$_{3}$. The critical
field lowered by the applied pressure is explained by a suppression of the
metastable blocked state, which is inherent to the phase separated manganite
system exhibiting the magnetic avalanche. To reduce a factor of the bad thermal
coupling in the bulk sample, and to further examine the nature of the
magnetization jump, we have performed the influence of pressure on the
isothermal magnetization of the powder sample. There is no discrepancy in the
critical field between the bulk and powder samples although the $MH$ curve of
the latter is not saturated at high fields. These findings indicate a crucial
role of the frozen phase separated state in the abrupt transition.
