BOSTON -- Terry Francona was asked Tuesday about the maturity of outfielder Josh Reddick as it pertained the plate approach, the persistent knock on Reddick throughout his ascent through the Red Sox system.

The endorsement Francona offered was more backhanded than the shots being hit at Wimbledon this week.

"He's a little streaky about plate discipline, but it's better than being bad," Francona said.

Reddick came into this season clearly behind Ryan Kalish on the minor-league depth chart in the outfield. It's Kalish, not Reddick, who is widely presumed to be poised to inherit the job in right field next season once J.D. Drew departs.

But with Kalish out, rehabbing a shoulder injury suffered in late April, it was Reddick who got the call when Carl Crawford went on the disabled list. He's made the most of his chance. With a double and a triple on Tuesday night, he boosted his slugging percentage to .667 in 21 big-league at-bats this season.

"I'm just getting good pitches and swinging at them and luckily not missing most of the time, so it works out for me," he said.

That comes after two months in which Reddick slugged over .500 at Triple-A Pawtucket. His batting average (.230) and on-base percentage (.333) didn't stand out, but he hit nine doubles and 14 home runs in fewer than 200 at-bats.

Even his plate approach has seemed to improve. Reddick already has more walks (33) this season than he had in a full season with the PawSox a year ago (25). If you combine his major-league and minor-league numbers, he's two shy of his career high for walks for any full season -- and it's not July 1 yet.

And then there's the matter of his power. He hit 18 home runs for the PawSox last season and then hit eight more home runs in April. His triple in the third inning Tuesday came on a low line drive that rolled into the right-field corner, but his fourth-inning double was a rocket off the center-field fence.

"When he swings at strikes," Francona said, "he's got a little thunder in that bat."

Twitter: @brianmacp