I would say 2 1/2. Belly and back are parallel but has that thin waist and legs look a little long for his body.
I think the point is, if he was 2.5 years old now then he was born in January. Deer don't have their half birthday until the fall so technically he is only 2 right now, not 2.5. Technicalities I know, I am just explaining what was implied above. Anyway, he looks like a nice buck, I would hold off and give him another look next year, he has some potential to make some really big gains if he's that big and truly only in his second year. <--- see what I did there?