That rumor made no sense. The Hawks could re-sign Horford to the max and be under the salary floor. I think either Stein misinterpreted someone or people are misinterpreting Stein.
If the Hawks are looking to trade those picks, it's presumably to package them for a veteran player who makes near Teague money but does not play PG, thus making Horford more likely to stay. The picks combined are $3.2 million -- that's not standing in the way of them doing anything.