DES MOINES, Iowa (AP) – Iowa coach Fran McCaffery says sophomore guard Devyn Marble is being held out of preseason practices with a concussion.  McCaffery said Thursday during Big Ten media day in Chicago that Marble suffered a concussion less than a week into fall practice, which began on Oct. 15.  McCaffery says Marble, who averaged 5.7 points a game last season, looks and feels fine. But McCaffery says Marble still has to pass a variety of tests that “aren’t going as well.”  McCaffery also says center Andrew Brommer hurt his knee on the first day of practice and won’t be ready to play for another three weeks.  Iowa opens its season against Chicago State on Nov. 11.