A little catch before Tuesday's game was all it took to destroy his optimism.
Toronto placed the starting pitcher on the 15-day disabled list with right forearm tightness one day before Johnson had been scheduled to face the Boston Red Sox.
The 29-year-old right-hander called the latest twist in his first season with the Blue Jays a huge disappointment, especially after his last start showed promise of a turnaround.
"I finally felt comfortable on the mound. I felt good. I felt like I was getting on top of the baseball and doing what I needed to do to get outs," said Johnson. "Now I'm not able to go out there on the mound. It's frustrating."
Johnson had felt soreness after his start in Seattle last week, but said the arm felt great a few days later and gave him no reason to worry.
The outing against the Mariners, five hits and no runs allowed through five innings, gave general manager Alex Anthopoulos reason to think Johnson (2-8, 6.20 earned-run average) was progressing near the end of a lousy season.
"It's disheartening," said Anthopoulos. "Just with the way he pitched last time, it looked like he was going to get it going."
The Blue Jays opted to give Johnson extra rest Monday when his start was skipped in favour of J.A. Happ, who was placed on the bereavement list after the game. Johnson's outing was delayed once more by the callup of Todd Redmond from triple-A Buffalo.
But he felt tightness while playing catch prior to Tuesday's game, Johnson described it as a "little grab" in his forearm as he was about to release the ball, and that was all it took for a trip to the DL.
"Before last start it was the best I felt in three years," said Johnson. "I felt great, everything, shoulder, elbow, everything felt right where it needed to be. I don't know what happened but in my last start I was a little sore and tight. I came in the third day, after the day off, I just felt great that day."
The Blue Jays called up right-hander Thad Weber from Buffalo to fill Johnson's roster spot. Anthopoulos said either Weber or Esmil Rogers could replace Johnson for Wednesday's game against the Red Sox.
Anthopoulos added Johnson would have an MRI either Tuesday or Wednesday. After that the team would know whether the injury is temporary or if they need to shut down Johnson for the remainder of the season.
"A lot of it is going to depend. If it's one of those things where he just needs a little bit of time then it could be shorter term. But if he needs to be shut down for a while and built back up to start, it really varies how long he needs to be shut down, and also what the MRI is going to tell us," said Anthopoulos. "To try to guess, it's just too early."
Blue Jays fans expecting Anthopoulos to use Johnson's injury as an excuse to give well-regarded prospects Marcus Stroman or Sean Nolin a major-league look shouldn't get their hopes up.
"Right now, especially with the way it's lined up and we need a starter for tomorrow, it's as much about who's on turn at this point," said Anthopoulos. "So you might see one of those guys the next time out, five days from now or something. We're not that far ahead. With the timing of this, you're limited with your options because of that start tomorrow."
Johnson, who came to Toronto in the off-season blockbuster trade with the Miami Marlins, has a history of injuries. He needed Tommy John surgery in 2007 and missed most of 2011 with shoulder injuries.
The six-foot-seven, 250-pounder who the Blue Jays had hoped would add firepower to their rotation is a free agent at the end of the season. The stats, and now another injury, don't add up to a big contract offer in the winter.
Right now, Johnson just wants to throw the ball.
"It's been tough, but still got to find a way to get back on the mound," he said. "That's the only good part about it is being out there. Even though I was struggling, I was out there, I felt great while I was out there. So, it's very frustrating."