In that June 21, 2008, debut vs. the Yankees, Thompson pitched five scoreless innings but was sent down following his third start with a 6.91 ERA. A strained shoulder at Triple-A Louisville kept him out a month later that summer. In 2009, he was limited to nine starts in the Minors because of three stints on the disabled list with right elbow inflammation. In August of that season, he had season-ending shoulder surgery to repair a frayed labrum.
By the end of the '09 season, Thompson was taken off the 40-man roster. But the 2010 season might have been the most trying year of all.
Because of time on the DL again, Thompson was limited to 12 starts at Double-A Carolina and three more with the Arizona Rookie League. He was 0-5 with a 3.71 ERA at Carolina with 11 walks and 52 strikeouts over 51 innings.
"The year he had, in a capsule, could be called 'frustrating,'" said Reds Minor League director Terry Reynolds. "He had one trying physical issue after another -- not just with his arm. He had mono and the flu and a lot of non-arm related issues."
The shoulder problems didn't entirely go away as well. He was often bothered by inflammation.
"This year, my season has been pretty bad," Thompson said. "[It was] up and down, as far as getting hurt again. It got to the point where I started getting mentally weak in the middle of the season. It felt like every time I tried to come back, I always had a setback or something was going on."
The Reds had Thompson get some extra work in their instructional league camp after the regular season. After that finished without incident, Thompson was extended some more in the Arizona Fall League. Through four games, including three starts, he had a 0.75 ERA with five walks and 12 strikeouts over 12 innings.
"He wouldn't be here if we didn't think he had the potential and could regain his old form," Reynolds said. "We look forward to seeing him in spring and getting 100 percent."
Both Reynolds and general manager Walt Jocketty have watched some of the outings in person. On Monday, Thompson was named the AFL's Pitcher of the Week.
"Pretty impressive," Jocketty said. "With Daryl, it's a matter of staying healthy enough to be able to perform for us."
"I feel like everything is starting to fall in place. I feel pretty good," Thompson said. "My arm has been bouncing back, recovering pretty good."
To say the pitching landscape on the Reds has changed since Thompson's first big league stint would be a huge understatement. Cincinnati currently has more arms than vacancies in a rotation filled with younger pitchers like Johnny Cueto, Mike Leake, Travis Wood, Aroldis Chapman, Sam LeCure and Matt Maloney. They are behind veterans like Bronson Arroyo and Edinson Volquez.
The Reds will have to decide soon whether to add Thompson back to the 40-man roster or risk exposing him to the Rule 5 Draft.
"It's rough. You have some really, really good young arms coming through," Thompson said. "I kind of showed what I could do in the past, but my past two years have been pretty rough and I haven't been able to do anything really.
"It's pretty much like getting drafted again. You have to prove yourself all over again and show them that you are healthy and ready to go. That's my goal -- stay healthy, go out there and feel good and be able to recover."