ST. LOUIS -- Jackie Bradley Jr. figured it was just another out.

Never mind that the Boston Red Sox center fielder had barreled a 90 mph sinker, low and away, the other way to the gap in left-center field in the second inning Tuesday night. Bradley has struggled so much over the past month that it seems he has stopped giving himself the benefit of the doubt. Even the well-hit balls have started to feel the same as the ones that die on the warning track.

"If you go look at my replay, I put my head down and threw my bat to the side. I promise you," Bradley said. "I didn't think I got all of it. I thought it was going to be caught."

Well, it wasn't caught, and not for a lack of trying, either. St. Louis Cardinals center fielder Dexter Fowler leaped at the wall but couldn't bring back Bradley's third homer -- and only his fifth extra-base hit -- in 88 plate appearances this season. The solo shot gave the Sox a two-run lead en route to a 6-3 victory in the opener of a two-game interleague series at Busch Stadium.

So, Bradley surprised even himself. He'll take it, of course, especially considering his numbers entering the game. Of the 267 major leaguers with at least 75 plate appearances, Bradley ranked 261st in on-base percentage (.238), 251st in batting average (.182) and 258th with a .537 OPS that was lower than the slugging percentage of 38 players.

All together now: Blech.

The Red Sox have come to expect more from a player who broke through last season as an All-Star with 30 doubles and 26 homers. And when manager John Farrell benched Bradley for all but one pinch at-bat in three recent games -- all against right-handed starting pitchers, no less -- he also described him as "pivotal to us for many reasons." The point, quite clearly, was to give Bradley a few days to clear his mind, work on his swing and get back on track, not to simply sit him in favor of veteran Chris Young, who is best used as a fourth outfielder at this point in his career.

But the Sox have come to expect extreme streakiness from Bradley, too. When he's hot, the way he was during his 29-game hitting streak last season, he can carry the offense every bit as much as Mookie Betts or Dustin Pedroia. But when he's cold, as he was over a 33-game spell last summer when he went 20-for-121 (.165) with a .560 OPS, he's one of the least productive hitters in the league.

With Bradley, there never has been much in between.

Farrell says he believes a hot streak is coming when he sees Bradley hit the ball to left-center field. It's when Bradley tries to pull everything to right field, according to Farrell, that he begins to go cold. In that case, the opposite-field homer and a single to left field in the seventh inning must have been positive signs for Bradley, right?

"You know you feel good," Bradley said of whether he can tell when he's about to go on one of his tears. "You can't necessarily bank on results, so to speak, because you can hit the ball hard and don't have anything to show for it, or you can hit the ball soft and have plenty to show for it. I'll take the results over hitting the ball hard."

By now, the Red Sox will tolerate the bad Bradley because they know how valuable the good Bradley can be. And they need the good Bradley more than ever. Without retired icon David Ortiz to rely on, Bradley, rookie Andrew Benintendi and Mitch Moreland are the left-handed hitters capable of doing the most damage in a batting order that leans decidedly to the right with Pedroia, Xander Bogaerts, Hanley Ramirez and Betts, who just so happened Tuesday night to smash his 10th career leadoff homer to tie Jacoby Ellsbury for the franchise record.

Before the game, Farrell was asked about the Red Sox's lack of production at third base and whether light-hitting fill-in Deven Marrero might merit playing time even after Pablo Sandoval (knee sprain) returns from the disabled list, possibly as soon as next week.

"Given the way the bottom half of our lineup has been for a little bit of time now, the ability to impact the baseball in the bottom third would be important," Farrell said.

As much as anyone, it's Bradley to whom the Red Sox are looking to provide that boost.

Perhaps Tuesday night was a step in that direction, even if Bradley didn't know it.