DETROIT >> With as good as Joe Nathan felt in an impromptu mound session on Saturday, it just means that a decision is looming.Nathan is eligible to return from the 15-day disabled list on Wednesday and, while manager Brad Ausmus isn't sure if he'll return then, a more important question isn't when, but rather to which role will he return?Joakim Soria has been perfect in four save opportunities since Nathan went down with a strained elbow, and pitched a 1-2-3 ninth inning to earn the win in Friday's series opener against the White Sox.