Jakob Forsbacka Karlsson and Trent Frederic could become good NHL centers. The Bruins are counting on it.



It is not their fault, however, that they are simply not ready for varsity status this season, not with seven possible run-ins against John Tavares, Auston Matthews and Nazem Kadri in April. The center talent runs deep in Tampa Bay, too, where Steven Stamkos, Brayden Point, Tyler Johnson, Anthony Cirelli and Cedric Paquette are options for the Lightning.



Charlie Coyle, 26 years old, has not yet and might never now become the offensive force the Sharks projected when they drafted him in the first round in 2010. League observers still scratch their heads when they recall that San Jose landed Brent Burns from Minnesota in a Coyle-included package on June 24, 2011. Now, Coyle is on his way to Boston, landed for a package of Ryan Donato and a fifth-round pick.



But even if Coyle has fallen short of the promise coiled within his 6-foot-3, 220-pound body, he...