Remember collecting and swapping bubble gum cards as a kid, you’d sometimes hedge a transaction by calling “trade backs” – a way to get your Dave Keon or your Frank Mahovlich back if you ever had buyers’ remorse? It makes wonder if the Anaheim Ducks and the Ottawa Senators can do some sort of version of trade backs this summer, when the NHL trading season heats up, upon completion of the 2014 Stanley Cup final. Potentially, there are three attractive centres that might be available – the Senators’ Jason Spezza, the Vancouver Canucks’ Ryan Kesler and the San Jose Sharks’ Joe Thornton – and Anaheim will likely be in the discussion for all of them. Let’s start with Spezza and why that trade might be the best fit for the Ducks. A year ago, the Ducks traded away Bobby Ryan to the Senators and in exchange received a first-round pick, a prospect (Stefan Noesen) and a young player (Jakob Silfverberg). The decision to move Ryan was made largely for contract reasons. The Ducks are a mid-cap team and with new contracts for both Ryan Getzlaf and Corey Perry kicking in, there wasn’t going to be enough money left over to pay Ryan. Getting a handful of futures made sense, especially since the Ducks have done an excellent job of grooming possible replacements for Ryan, with Devante Smith-Pelly, Emerson Etem, Patrick Maroon and Matt Belesky, all providing size and varied levels of skill on the wing. But when the Ducks fell short this spring, losing in the second round to the Los Angeles Kings, the perception was that they didn’t match up well enough down the middle. The Kings ran Anze Kopitar, Jeff Carter, Jarret Stoll and Mike Richards at them. The Ducks countered with Getzlaf, Mathieu Perreault, Saku Koivu and Nick Bonino. That is a mismatch of the first order. So Anaheim is interested in adding someone to support Getzlaf and ideally would like to do it without breaking the budget. Spezza would be an attractive option, in part because the actual cash outlay on his current contract, which expires after the 2014-15 season, is $4-million (even if the cap hit comes in at $7-million).