The pitch left his hand in this July 1996 contest against Oakland at Toronto's SkyDome and Mark McGwire turned it around into the dome's fifth deck - 488 feet away.
"Did I watch it? Oh, yeah. I've never seen a ball hit that far," Flener told The Los Angeles Times later, "and I don't think I ever will again. I just thanked God no one was on base."
Five years later, there was also little Flener could do when a winter ball pitch came screaming back at his face, according to a Times story later.
This time, in January 2001, there was no watching the ball afterward. This ball hit Flener square in the right eye, destroying it, and his sight in that eye, instantly.
It also ended any hope of Flener resuming his major league career.
Flener's career began in 1990, taken by the Blue Jays in the ninth round of the draft, out of Cal State-Fullerton.
With the Blue Jays, Flener started at rookie St. Catharines, getting 14 outings, seven starts. He made single-A Myrtle Beach in 1991, then high-A Dunedin in 1992.
In 1993, he made AA Knoxville, going 13-6 over 38 outings, 16 starts, with an ERA of 3.30. That September, he earned his first trip to Toronto.
With the Blue Jays that September, Flener got into six games in relief, giving up three earned runs over 6.2 total innings.
Flener didn't return to the majors until 1996, seeing his 1994 season cut short due to elbow surgery. He then spent 1995 completely with AAA Syracuse.
It was in July 1996 that Flener made his return, getting into 15 games, 11 starts. He went 3-2, with a 4.58 ERA. After making it back, Flener told The Associated Press he was happy to be back.
"After being hurt and having a year taken from me, I'm much more appreciative now," Flener told The AP. "Now I can play in beautiful yards like this, and I'm very happy about that."
Flener came back for eight more outings, one start, for Toronto in 1997, rounding out his major league career.
Flener, though, continued playing in the minors. In 1998, he played with the Indians at AA Akron and AAA Buffalo, then 1999 with the Mariners at AAA Tacoma. In 2000, he moved to the Padres and AA Mobile.
Then, that winter of 2000-2001, Flener went to Venezuela to play winter ball. He told The Times he could see the ball come back at him, but he couldn't pick up its path. It hit before he could do anything. His eye was gone.
The Times spoke with Flener two weeks later, with Flener already making plans to move on, plans he had to make.
"I will find a decent job and I have a great family," Flener told The Times. "To me, this just feels like the next stop. I don't feel sorry for myself. Things a lot more tragic have happened to other people. If anything, my story is just a career cut short."
- Youngstown Vindicator, Associated Press, July 31, 1996: Newcomers play well, vets need the work, Part 2
- Los Angeles Times, Aug. 4, 1996: McGwire's Homer Didn't Floor Flener
- Los Angeles Times, Feb. 5, 2001: Shattered Dream
Made the Majors: 698 - 55.7%-X
Never Made Majors: 556-44.3%
5+ Seasons in the Majors: 299
10+ Seasons in the Minors: 178