BOSTON — The Red Sox were riding high going into the sixth inning against the Kansas City Royals on Sunday.
The club had just turned in a three-run fifth inning to pull ahead of the defending World Series champs, and starter Eduardo Rodriguez, though shaky through the first couple innings, had been getting the Royals to put some weak contact on the ball to hold them at bay from the third on.
And then he walked Royals first baseman Eric Hosmer to start the sixth inning.
While leadoff walks generally are a bad sign, this one set off a chain reaction. Rodriguez gave up a ground-rule double to designated hitter Kendrys Morales before walking Salva…