LSC has a clear tendency to place subordinate clauses in peripheral positions of the sentence. This is also the case of relative constructions, which can only be placed in preposed and postposed positions.
Preposed:
[book yesterday buy (self)] joan bring not.
‘Joan did not bring the book he bought yesterday.’
(recreated from Mosella, 2012: 203)
Postposed:
joan bring not [book yesterday buy (self)].
‘Joan did not bring the book he bought yesterday.’
(recreated from Mosella, 2012: 203)
Both positions are possible, with the preposed position being the preferred one.