This Player Mover works by queing up any calls to MovePlayerByAmount or MovePlayerToPosition and then executing the position changes on the next FixedUpdate call (or immediately if the calls are made from FixedUpdate). Use this if your player absolutely has to be moved in FixedUpdate!
You can add this component by selecting a game object and then selecting from the Top Menu Bar:
Component -> Deep Space Labs -> -> SAM -> Player Movers -> Fixed Update Player Mover
or by selecting a game object and using the Add Component menu via its inspector:
Component -> Deep Space Labs -> -> SAM -> Player Movers -> Fixed Update Player Mover
In order to support the enabling of the 'Perform Shift In Single Frame' option on World Shifters, any World Shifters which are set to shift an Active Grid using a Fixed Update Player Mover must have their 'When To Shift' setting set to Fixed Update, as that is the only way to make the Fixed Update Player Mover work in immediate mode!