Depending on the exact model specification, money can play an explicit role in the determination of output and inflation.3 However, it usually plays only a passive role (if it plays a role at all): Money demand is determined by the other variables of the model but money has no effect on them.4 Given this more or less unimportant role for money in New-Keynesian models, some observers already see money leaving the stage of the academic discussion on monetary policy.
However, I think that a few qualifications are essential. First of all, I would argue that there is an implicit key role for money in the basic New Keynesian Model.5 For instance, implementing a certain path of the short-term interest rate is only possible if the central bank can control the corresponding supply of base money.