BOSTON - What had caused the Red Sox to raise their hopes to a season high was the way they had come back. They repeatedly came back from deficits to win games recently and they had made an impressive recovery from a 10-game deficit to achieve a breath of life and a sniff of the division race.
A big part of all that was Clay Buchholz, their best starting pitcher, who had boosted their mini-revival and carried them into the opener of a surprisingly big series against the Yankees with new hope. Then he left the game in the fourth inning with what the club called "elbow tightness" and the Red Sox were left looking at a problem from which they might not be able to come back.
The thought of losing Buchholz, the anchor of an iffy staff, seems a lot worse for the Red Sox than the memory of losing to the Yankees, 5-1, in the opener of what might be a make-or-break three-game series.
"It would be huge," centerfielder Mookie Betts said. "He's been throwing the ball great every outing, giving us a chance. Hopefully, he heals quickly."
A vague description such as "elbow tightness" is the sort of thing that can make fans of any team say "Uh-oh."
Friday night, it didn't matter so much to the Red Sox that their recent momentum after a disjointed, dysfunctional start took it on the chin and that they fell 6 1/2 games behind their first-place rival. The first concern was about the man who summoned catcher Sandy Leon to the mound after making a pitch that felt awkward.
Up until then, no one had seen any sign of trouble. "Actually, from field level, the way he was throwing the baseball, he had good action on all his pitches," manager John Farrell said. "He called Sandy out after the last he threw. Clay had mentioned he felt a little stiffness and didn't feel like he could push through it at that point."
Leon said Buchholz's cut fastball usually travels at 88 or 89 miles an hour, but that last pitch was 84 or 85.
"He called me in and said he felt something in his elbow. That's all I know," Leon said. "I just said, 'You've got to be smart. We've got a long season, we've got three months to go. You've been doing a good job.' ''
Farrell said Buchholz had an MRI and that the team was waiting for the results of that test and the rest of what he called "a full work-up."
Buchholz's teammates made a mess of that inning after he left, committing two errors and allowing three unearned runs.
Shortstop Xander Bogaerts said the team didn't lose focus. Things just happened.
One thing you've got to say about the Red Sox: They're never dull.
Credit them for adding world-class hitters Pablo Sandoval and Hanley Ramirez during the offseason. They overcame a wacky episode in which Sandoval was benched for Instagramming about a woman's features during a ballgame.
Then there is the fact that the Sox are the only team whose lone All-Star might be out of a job soon.
Utility player Brock Holt was named to the American League squad, becoming the first All-Star in history to play all four infield positions and all three outfield positions before the break. Lately, he has been the everyday second baseman. But the team doesn't know where it will put him once starting second baseman Dustin Pedroia returns from the disabled list.
"He'll move around, as he has been," Farrell said of Holt.
That is a matter for another day. The Red Sox seem to have their hands full right now. "It's one game," Betts said. "We've got to go get 'em tomorrow."
But you have to wonder if this comeback team has found something it can't come back from.