its a weird one - they are supposed to have come to middle earth at the same time, i.e. the 3rd age (according to multiple references from tolkein), but 'the peoples of middle earth' says the 2 blue wizards came in the second age - so a bit of a contradiction from tolkein.
They both came together (the blue ones, according the peoples reference) though and there's no sign of another.
i will be annoyed if its gandalf as thats quite a change from the lore - he has nothing to do with the 2nd age at all and was on Valinor at the time.
But who else it could be i don't know
IIRC the 2 blue wizards pop up briefly around this point in time, but don't really do much - stir up a bit of dissent within the people who were allying with Morgoth or something like that - then nothing until they are sent again later.
Gandalf supposedly visited a couple of times briefly before events of the PJ movies but the inference is more early in the 3rd age rather than the era of this show but it is pretty vague and he does less than even the blue wizards - basically just sight seeing.
Gandalf supposedly visited a couple of times briefly before events of the PJ movies but the inference is more early in the 3rd age rather than the era of this show but it is pretty vague and he does less than even the blue wizards - basically just sight seeing.