RowCount Is Returning Null

i have 2 stored procedures: a delete and a select.  the delete sp returns the rowcount properly.  the select returns null.  the code for both sp's is extremely simple and extremely similar.  when i execute the select sp in server management studio the rowcount shows a 1 as expected.  but the calling method gets null.

SP Code 

ALTER PROCEDURE [dbo].[RetrieveEmployeeKeyFromAssignmentTable]

@assignmentPrimaryKey int,

@rowCount int OUTPUT

AS

BEGIN

SET NOCOUNT ON;

SELECT employeePrimaryKey FROM assignmentTable WHERE primaryKey = @assignmentPrimaryKey;

SET @rowCount = @@RowCount;

END

c# code

SqlConnection conn = GetOpenSqlConnection();

if (conn == null)  return true;

SqlDataReader reader = null;

SqlParameter p1 = new SqlParameter();  SqlParameter p2 = new SqlParameter();

try {

SqlCommand command = new SqlCommand();

command.CommandText = "RetrieveEmployeeKeyFromAssignmentTable";

command.CommandType = CommandType.StoredProcedure;

command.Connection = conn;

p1.ParameterName = "@assignmentPrimaryKey";

p1.Value = assignmentPrimaryKey;

p2.ParameterName = "@rowCount";

p2.Direction = ParameterDirection.Output;

p2.Value = 0;

command.Parameters.Add(p1); command.Parameters.Add(p2);

reader = command.ExecuteReader();

if (p2.Value == null) //always true

any suggestions would be appreciated.

thanks.  matt