Detroit's middle infield problem

The Tigers will regret it if they don't replace Jhonny Peralta and Omar Infante. US PRESSWIRE, Getty Images

It's often said that the best way for baseball teams to build a championship squad is up the middle, with middle generally referring to catcher, second base, shortstop and center field. In Austin Jackson and Alex Avila, the Detroit Tigers -- a team with World Series aspirations -- have half of that equation solved, but second base and shortstop could once again grow to be the team's Achilles' heel.