PHILADELPHIA — He’s started less than half of the 145 games he’s played in the past three seasons, and he’s only played in 71% of the games his teams have played in that span. He’s averaged 7.1 points and less than 20 minutes per game. The Sixers are his sixth team in four seasons. He’s 33 years old. So, why was signing DeAndre Jordan so important? Why might the Sixers’ postseason fate lie in Jordan’s ability to give Joel Embiid 12 minutes of quality rest? Good questions. The answers started coming Monday night, when the Sixers hosted the Bulls — answers that sort of hide in the weeds, either …