By now, the Pistons have already faced the Boston Celtics, Miami Heat, Philadelphia 76ers and New York Knicks as their opening four-game slate, so Detroit has been getting the job done against a collection of teams that were summarily expected to be contenders for the Eastern Conference crown. But to make the Pistons’ defensive effort even more impressive, they’ve done so without Jalen Duren, who is still recovering from a strained right hamstring.