I personally don't think he is a strong Christ figure. There are some reasons for the comparison, however. Romero goes into the ring to fight with two other bull fighters, just as when on the cross, Christ was flanked by two others -- the two thieves that were crucified with him. Also, the soldiers fought over Christ's robe at the cross, and Romero takes his cape off and gives it to Brett as part of the bull fighting tradition. Although it is possible for a bull fighter to die in the ring, and thus, in a sense, be giving up his life, Romero does not die in the ring. Also, Romero is not sacrificing himself for anyone as Christ did. In chapter 18 when he fights the bulls and has dedicated the fight to Brett, it says:
But he did not do it for her at any loss to himself. He gained by it all through the afternoon.
Christ did what he did not for himself, but for others, and at a great cost to himself. So, I don't think Romero is a true Christ figure.