When Dustin Pedroia agreed with the Sox to an eight-year, $110 million extension during the 2013 season — one that (based on deferrals) represents an annual $13.3 million payroll hit for luxury tax purposes — the second baseman did so at what was widely viewed as a below-market rate. His longtime peer, Robinson Cano, was nearing a 10-year, $240 million payday on the open market.