Price was pulled from his scheduled Friday home start against Kansas City with a recurrence of the same issue that delayed his start to the season until May 29.
The Kansas City Royals look to keep rolling while building on their eight-game winning streak.
The Royals began their nine-game road trip by sweeping the Detroit Tigers and capped the series with a 16-2 victory on Wednesday - the second time in the last seven games that they pushed across 16 runs.
Price, who was traded to Toronto in the 2015 season, signed with Boston before the 2016 campaign, in which he went 17-9 with 228 strikeouts and a 3.99 earned-run average.
The Boston Red Sox made it back from the west coast still in first place in the American League East, but things certainly could have gone better. David Price gets the ball, and he is 5-3 with a 3.82 ERA and 63 strikeouts this season.
The Royals held off Boston for a 4-2 win on Friday to open this series.
As has been the case for much of July, the Sox struggled with runners in scoring position, finishing the night 1-for-6.
According to oddsmakers at Bovada.lv, Boston is the favorite at home today, as the Red Sox are getting odds of -140 to win, while the Royals are listed with odds of +125 to win.
Jason Vargas (13-4) gave up one run and five hits in six innings. Price has an ERA well under three at home this season and pitched a shutout in his last start at Fenway.