SQL Server 2012 :: Can't Get Row Count To Return To Calling Stored Procedure

SQL Server 2012 Standard SP 1.

Stored procedure A calls another stored procedure B. Rowcount is set properly in called procedure B, but does not seem to return it to calling procedure A. Otherwise the two stored procedures are working correctly. Here is the relevant code from the calling procedure A:

declare @NumBufferManagerRows int = 0;
exec persist.LoadBufferManager @StartTicks, @EndTicks, @TimeDiff, @NumBufferManagerRows;
print 'BufferManagerRows';
print @NumBufferManagerRows;

Print statement prints @NumBufferManagerRows as 0.

Here is the called stored procedure B:

CREATE PROCEDURE [persist].[LoadBufferManager]
-- Add the parameters for the stored procedure here
@StartTicks bigint,
@EndTicks bigint,
@TimeDiff decimal(9,2),
@NumRows int OUTPUT

[Code] ...