Griffey hadn't played since April 12 when he left in the middle of a game at Chicago with a hyperextended knee. He was later diagnosed with a strained tendon in the back of the knee and placed on the DL a few days later.
The decision for his return wasn't entirely Griffey's. General manager Wayne Krivsky, manager Jerry Narron and medical director Dr. Tim Kremchek all had input. Despite the potential hazards from a wet field after a full day of rain, the green light was still given.
"Everybody was concerned about that, but talking with doctors, Wayne and Griff, he wanted to play," said bench coach Bucky Dent, who filled in Thursday while Narron attended his daughter's college graduation in North Carolina. "Everybody said it was OK, so he's going to go."
Narron made out the Reds lineup on Wednesday night before leaving town. The manager was due to return during the game. Once the decision to activate Griffey was finalized, outfielder Chris Denorfia was optioned to Triple-A Louisville to make room on the roster.
"There were a couple of scenarios in case he didn't go that we talked about," Dent said. "Last night, we talked about the one if he was in there. That's the one I posted."
Griffey, who batted .258 with two homers and seven RBIs in eight games before his injury, has been eligible for activation since April 28. His status was originally believed to be day-to-day, but his recovery endured several delays.
On Monday and Tuesday, the 36-year-old underwent the most rigorous running drills of his rehabilitation and showed he could run the bases and turn corners at full speed.
Griffey conceded his knee wouldn't have to be 100 percent to play.
"I'm going to play with some pain," Griffey said. "It's whether or not you can stand it."
Ranked 12th on the all-time list with 538 career home runs, various injuries have marred several of Griffey's seasons in Cincinnati. In 2002, he tore the patellar tendon in the same right knee and played just 70 games. An ankle injury limited him to 53 games in 2003 and a torn right hamstring kept him at 83 games in 2004 and put his career in jeopardy.
Rehabilitating from radical surgery that re-attached his hamstring to the bone, Griffey returned with a strong 2005. Playing 128 games, he batted .301 with 35 home runs and 92 RBIs and earned National League Comeback Player of the Year honors.
Healthy all winter, Griffey appeared poised to build on last season when he batted .524 with three home runs during the inaugural World Baseball Classic.
The Reds posted a 17-9 record during Griffey's absence and entered the night in first place in the National League Central. Griffey liked how his teammates responded while he was out.
"They don't give up," Griffey said. "Every day, they're pretty much the same. They don't get too high or too low. Everything is, 'Hey, we'll take what they give us.' When things happen not in our favor, they don't get too down. It's fun to watch."
Despite the Reds' recent success, the slugger's presence was still missed in the order.
"We need him in there," right fielder Austin Kearns said. "He brings things to the table no one else does. It'll help."