Jackie Bradley Jr. could feel sorry for himself. Remember the sensational spring training that gained him a spot on the Red Sox Opening Day roster, to say nothing of comparisons to bygone outfield phenom Fred Lynn? Well, an 0-for-20 skid washed it all away, initially landing Bradley on the bench before David Ortiz’ return from the disabled list punched the youngster’s ticket back to the minor leagues. In less than a month, he has gone from the Next Big Thing to a prospect-in-exile. So, yes, Bradley could sit at McCoy Stadium, an hour’s drive from Fenway Park, and brood over opportunities missed. He could relive his groundout with a runner on third base in the April 10 game against the Orioles or the pair of four-pitch strikeouts on back-to-back days against Rays starters Alex Cobb and Jeremy Hellickson. But that never has been Bradley’s way. Since his days at the University of South Carolina, he has received praise from coaches and scouts for his age-defying maturity (baseball people call it “makeup”) and his ability to deal with adversity. Why, then, should this be any different? “I know I can play at the highest level,” Bradley said Thursday before going 2-for-4 with a walk for Triple-A Pawtucket. “Even last year, when I was in high-A and Double-A ball, I told myself, ‘I can play there now.’ It’s just the way I carry myself. That’s what I believe. Nothing like this past month is going to break me, hurt my confidence. It’s going to take a whole lot more than that.” ‘Off the charts’ Bradley repeated all the same things last week during a half-hour sitdown with PawSox manager Gary DiSarcina. Having barely met Bradley in spring training, DiSarcina wanted to get better acquainted with the 23-year-old outfielder and gauge his state of mind after being demoted April 20. If anything, he found Bradley to be defiant, refusing to let a 3-for-31 start to his major league career define him. “He’ll say to your face, ‘Everything’s all right. I’m good, I’m good.’ But you look at his numbers, and I’ve sat there, I know it’s not good,” said DiSarcina, a 12-year major leaguer with the Angels. “He’s experiencing failure for the first time — at the big league level, on the big stage in Boston. That’s tough on anyone. But he’s going to be fine. His makeup is off the charts.” And that was a big reason the Red Sox felt comfortable breaking camp with Bradley in the first place. All along, manager John Farrell said Bradley would remain in the majors as long as he was in the lineup almost every day. But unless Bradley kept up what was his unsustainable torrid spring training pace, Farrell also knew playing time would grow scarce once the soreness in Ortiz’ sore heels subsided. One National League scout noted last week that demoting a young player after his first call-up often leads to a “letdown” and risks stunting further development. But the Red Sox never feared that with Bradley, even though he hadn’t spent so much as a single day in Triple A.