Salgado is certainly a better attacker than Zebina, and he would give us that extra drive up the right flank. However, I consider his defensive skills to be not much better than that of Zebina's. Salgado sometimes is at fault for losing marks, however, his tackling is above average despite him being somewhat untimely.
Another issue we have here is that Salgado is obviously very poor in the air, and I'm not sure if it would be a good idea to field another short, inept player in the air in the back four. Zebina actually gives us more height and power, something we needed last year with all the difficulty dealing with crosses and highballs. Although, Zebina was outjumped by Zola at Cagliari last season, so I don't know. If we could get Salgado on the cheap, I say why not?