"Thank NFL for my first fine," Mercilus wrote on his official Twitter account. "Unfortunately I feel like it won't be my last as a pass rusher."
Mercilus was penalized for roughing the passer on a hit to Flacco's face during the third quarter of the Ravens' 30-9 win.
Flacco was unhurt, and the Ravens went on to finish the drive with a 1-yard touchdown run by running back Bernard Pierce.
Mercilus intends to appeal the fine.
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