The NFL is continuing to crack down on hip-drop tackles via the league’s disciplinary process, if not with penalties on the field.

Four players were fined for hip-drop tackles in Week Two, the league announced: Chicago’s T.J. Edwards, Kansas City’s Nick Bolton and the Jets’ C.J. Mosley were fined $16,883 each. The Rams’ Desjuan Johnson was fined $5,191.

The league did not explain the discrepancy in the fine amounts, but may have decided that Johnson’s hip-drop tackle was less blatant than the others.

The NFL defines a hip-drop tackle as when a defender wraps up a ball carrier and rotates or swivels his hips, unweighting himself and dropping onto ball carrier’s legs during the tackle. The technique has caused several injuries in the past and the league wants to get rid of it, but players have complained that it’s ill-defined and question whether it will be enforced consistently.