The sizzle was obvious. The substance, less so. On the Carolina Panthers’ second offensive play in Friday’s 27-20 preseason victory over the Miami Dolphins, the call was a simple run. But Christian McCaffrey exploded through the team’s offensive line and scampered 71 yards nearly untouched into the end zone. It was a spark, the sort the Panthers wanted more of from McCaffrey last season and are more dedicated to creating this year. It was the type of run where all of Bank of America Stadium stood up at once, and craned their necks to watch No. 22 sprint unabated. Everybody ... including the blockers who gave him the lane to run through. And it was the most unlikely of blockers who made some of