  Recent studies have shown possible connections between highly magnetized
neutron stars ("magnetars"), whose X-ray emission is too bright to be powered
by rotational energy, and ordinary radio pulsars. In addition to the magnetar
SGR J1745-2900, one of the radio pulsars in the Galactic centre (GC) region,
PSR J1746-2850, had timing properties implying a large magnetic field strength
and young age, as well as a flat spectrum. All characteristics are similar to
those of rare, transient, radio-loud magnetars. Using several deep
non-detections from the literature and two new detections, we show that this
pulsar is also transient in the radio. Both the flat spectrum and large
amplitude variability are inconsistent with the light curves and spectral
indices of 3 radio pulsars with high magnetic field strengths. We further use
frequent, deep archival imaging observations of the GC in the past 15 years to
rule out a possible X-ray outburst with a luminosity exceeding the rotational
spin down rate. This source, either a transient magnetar without any detected
X-ray counterpart or a young, strongly magnetized radio pulsar producing
magnetar-like radio emission, further blurs the line between the two
categories. We discuss the implications of this object for the radio emission
mechanism in magnetars and for star and compact object formation in the GC.
