"But you can't fully simulate a game in practice," Koskie admitted. "It's impossible."
Yet here he was in Dunedin, standing on the left side of the plate and staring at Jays starter Mike Maroth. The pitcher from Arkansas didn't make the transition back to baseball any easier for the 35-year-old from Manitoba. Maroth's fastball tailed inside and hit Koskie in the back, just behind the right shoulder.
The pitch arrived less than a foot from his head, but if Koskie had any trepidation in the seconds that followed, he didn't show it, as he trotted to first base and then scored from first on Pete Orr's double to left-center.
For Koskie, the at-bat and run scored didn't amount to a dramatic return to baseball. But for scrappiness alone, it was a perfect comeback for Koskie -- a player who built a reputation for giving it his all on the field in stints with the Twins, Blue Jays and Brewers.
It was that hard-charging drive that led Koskie, as a member of the Brewers, to dive for a ball in Milwaukee on July 6, 2006. He hit his head in the fall, and although the injury didn't appear serious, something terrible happened inside the ballplayer's head.
"I went from playing baseball to not being able to walk through doors," Koskie remembered.
He spent the next two years in doctor's office after doctor's office. No one could tell Koskie what was wrong, and he soon realized how little is known about concussions and the brain. In fact, one doctor told Koskie he had a social anxiety disorder, not a brain injury. He still laughs at that diagnosis.
"I played for nine years at the big league level," he said. "If I had social anxiety disorder, I think I'd have trouble playing in front of 40,000 people."
The problem with concussions, Koskie said, is that definitive diagnoses are difficult, if not impossible, to receive.
"There's no X-ray that shows you've got a broken bone," Koskie explained. "I've said many times that if I write a book, I'd call it 'If I Only Had a Cast.' People think you're fine, and the times they'd see you, you would be fine. But three days before, you couldn't leave your room because your head hurt."
Koskie worked hard to heal himself, finding his feet again in everyday tasks and eventually playing hockey with his kids. At the first of the year, he decided he wanted to play baseball again at the highest level. He called the Twins and asked if he could work out with the team. They agreed. A few weeks later, in February, Koskie signed a Minor League deal with the Cubs.
He'd fought his way back to baseball.
"I want to give some hope to people going through this injury," Koskie said. "It might take a little time, but there is light at the end of the tunnel. You can get back to life before your injury. Not everyone is going to be able to play Major League Baseball after a concussion, but to get back to somewhat of a normal life, that's all I wanted."
As a member of Canada's World Baseball Classic team, Koskie has faced the same question from reporter after reporter -- is he in the tournament to prove something to Major League Baseball? -- and the infielder dislikes the suggestion.
"I didn't play in this tournament just to prove to Major League Baseball that I was healthy," Koskie said. "This is more of what this represents for me -- what I've gone through in two and a half years. To be able to put on a Canadian uniform and be in this situation is a blessing."
Even so, Koskie did prove he was healthy in his first game back. He scored three times and smacked an eighth-inning double down the right-field line in Team Canada's 6-4 win over the Blue Jays.
"I felt good," Koskie said after the game. "We'll see how I feel tomorrow."