But following the demotion, the 20-year-old Johnston picked up nine hits in his first 13 at-bats with Boise, including a triple and four doubles.
"I talked to him a little about what went on in Peoria," Boise manager Tom Beyers said of Johnston. "He has to come up with some kind of two-strike approach. He really wasn't doing anything different when he got two strikes on him. That's one thing we're going to try to emphasize here."
For a fourth-round draft pick, Johnston has yet to perform like one.
Now in his third season with the Cubs, the product of Hamilton High School in Chandler, Ariz., has hit below .200 for much of his brief pro career. He was slowed by an ankle injury last season in his first Midwest League stint with Peoria and would miss the second half of the season.
As the result of his struggles offensively, Beyers worries that Johnston's confidence level has taken a beating.
"He really just hasn't had any success in pro ball yet," Beyers observed. "It's great that he's gotten off to a good start here. I think a lot of it (struggles) has to do with how he feels about himself confidence-wise."
Johnston admits that confidence – and comfort – is a big key to moving forward.
"That's basically what it all is for me," he said. "Just have to relax a little bit."
Johnston was plenty relaxed in his Boise debut on Tuesday night. He finished with a career-high four hits – including a pair of doubles and a triple – and followed that up with a two-hit performance the following night, and three hits on Thursday.
Already with Boise, Johnston has more multi-hit showings than he did in his recent two-plus months at Peoria, and the shortstop knows why.
"I'm seeing pitches," he said. "I've got a couple of fastballs to hit and my triple was on a changeup. I hit a double off the wall off a curveball. I was seeing everything and feeling a lot more comfortable."
Defensively, Johnston arrived in Boise with not much to brag about in the field, either, having led all Midwest League shortstops with 18 errors.
Most of those miscues were throwing errors, he said.
"The ball will tail off and end up off the mark," Johnston explained.
As such, Johnston has worked with Cubs Minor League Infield/Bunting Coordinator Bobby Dickerson to get more backspin on his throws.
His troubles in the field sound somewhat similar to another Cubs infield prospect – Triple-A Iowa third baseman Scott Moore. The majority of Moore's errors throughout his stay with the Cubs is the result of poor throws, too.
"Fielding-wise, I've been fine. I catch the ball all the time, but I've had a hard time throwing," Johnston said. "I think 14 of them (errors) were throwing."
Johnston began his pro career in the Arizona Rookie League with the Mesa Cubs two years ago and then bypassed Boise en route to Peoria last year. After struggling at the plate in much of his time there the past two seasons, he now has a fresh start in the Northwest League.
"It's a big confidence-booster," Johnston said, adding, "I haven't worked on much with my swing or anything at the plate. It's all about confidence."