It took about three weeks last year for Will Middlebrooks to notice that teams were pitching him differently after the Red Sox called him up from Triple A.

Jackie Bradley Jr. hasn’t had to wait so long.

After reaching base in six of his 14 plate appearances in the season-opening series against the Yankees in New York, Bradley had a slightly tougher time over the weekend at Rogers Centre against the Toronto Blue Jays. The rookie left fielder recorded one hit and two walks while striking out four times over his final 10 plate appearances.

In three days in Canada, “Jackie Mania” has lost some of its spring training steam.

“Pitch to pitch, at-bat to at-bat, you see them trying different things the more they get to know you, or think they know you,” Bradley said before going 0-for-4 in yesterday’s 13-0 win to lower his average to .143. “If they think, ‘He struggles with pitches inside,’ you just have to make sure you’re geared up for pitches inside.”

If anything, Bradley has appeared susceptible to inside fastballs, especially from lefties. It isn’t surprising either. Unlike in the minors, big league pitchers have access to video of each hitter, and with every game, the file on Bradley expands.

“They can run that two-seamer under his hands, and I’ve noticed some guys have started doing that,” Middlebrooks, the second-year third baseman who hit three homers yesterday, said. “It’s one of those things that, it looks good to him, but it’s a ball. He’s going to have to learn to lay off. That’s tough in your first week in the big leagues. You haven’t seen guys with sinkers like that. He’s a good enough player that it’s just something he’s going to have to get accustomed to. And he knows that.”

As the Red Sox return to Fenway Park for today’s home opener against the Baltimore Orioles, Bradley is 3-for-21 with six strikeouts. But he also has drawn five walks and has a .333 on-base percentage that is palatable but still far below his norms in the minor leagues.

Despite having never played a game above Double A, Bradley broke camp with the Red Sox after a stellar spring training in large part because designated hitter David Ortiz opened the season on the disabled list. But Ortiz is slated to play an extended spring training game today, and barring another setback with his sore heels, he’s on track to rejoin the team in late April.