Detroit enters at 45-17 on the season, still among the best records in the league, but the recent stretch has exposed vulnerabilities the Pistons need to address quickly. Saturday’s loss to the Brooklyn Nets, a 107-105 defeat at home as a 13.5-point favorite, was the kind of result that raises serious questions. The Pistons have now failed to score more than 109 points in four straight games and are 1-6 against the spread in their last seven contests.