During the September-October 2008 outburst of the accreting millisecond pulsar SAX J1808.4 - 3658 , the source was observed by both Suzaku and XMM-Newton approximately 1 day apart .
Spectral analysis reveals a broad relativistic Fe K \alpha emission line which is present in both data-sets , as has recently been reported for other neutron star low-mass X-ray binaries .
The properties of the Fe K line observed during each observation are very similar .
From modeling the Fe line , we determine the inner accretion disk radius to be 13.2 \pm 2.5 GM/c ^ { 2 } .
The inner disk radius measured from the Fe K line suggests that the accretion disk is not very receded in the hard state .
If the inner disk ( as measured by the Fe line ) is truncated at the magnetospheric radius this implies a magnetic field strength of \sim 3 \times 10 ^ { 8 } G at the magnetic poles , consistent with other independent estimates .