Cincinnati had to give up a major talent in Josh Hamilton but needed to fill a void in the pitching rotation.
The club brought in Volquez from Texas in 2008 and watched their young star kick off the season with a 7-1 record and a 1.33 ERA, allowing no more than one earned run in all but one of those starts. He went on complete a 17-win season with a 3.21 ERA in his first year in Cincinnati.
Both Volquez and Hamilton earned a trip to the 2008 All-Star Game, and the trade was considered a win-win for both sides.
Things didn't turn out as bright for Volquez his second year in Cincinnati, pitching just nine games before undergoing season-ending Tommy John surgery on an elbow that slowed him all year.
Volquez never found the same form he had in 2008, pitching back-to-back four-win seasons before a five-win Cincinnati finale in 2011.
Now with the Padres, Volquez (5-7, 3.68 ERA) will take the mound against the Reds on Thursday for the first time since his departure from the club.
"I'm excited. Yes, I am," Volquez said. "I spent four years there and I have a lot of friends there. I look forward to pitching against them. It's going to be fun."
And to make things even more interesting, he'll be facing off against the man the Reds traded for him -- Mat Latos.
Latos (7-2, 4.42 ERA) is seemingly having the opposite experience Volquez had in Cincinnati. While the 24-year-old already has accumulated seven wins this season -- second most on the squad -- he struggled early on, losing in his first two outings and jacking his ERA up to 8.22.
Latos hasn't recorded a loss since.
He's pitched two consecutive complete games, recording two wins while allowing a combined two runs. Latos also notched 20 strikeouts in the two outings, including a career-high 13 strikeouts in his most recent start against the Brewers, en route to garnering his first career National League Player of the Week honors.
"I'm not really necessarily going out there to be recognized," Latos said. "I'm going out there to try to win a ballgame and help out my ballclub. It's great to be the Player of the Week. It's good to have that little confidence boost. Back-to-back complete games is something that's rare, so it was good to throw those two games."
Reds: Rolen still resting
Third baseman Scott Rolen was out of the lineup again Wednesday for the fourth night in a row with lower back spasms.
Rolen has continued to receive treatments on his back, but general manager Walt Jocketty said a roster move may be in store.
"I'll know better probably the next day or so," Jocketty said. "We may end up doing something. He was feeling better today, so we'll see."
Rolen is currently listed day-to-day and said he hopes to return for the San Diego series.
"I'm mobile and walking around," said Rolen, who is hitting .184 this season. "No, I'm not comfortable. I'm not going to do any baseball stuff. I am getting around better, for sure, and improving. But I've not progressed to jumping jacks yet."
Through the first 81 games of the season, the Reds have only used their original five starting pitchers -- Johnny Cueto, Bronson Arroyo, Mat Latos, Mike Leake and Homer Bailey. The club broke its modern record of 79, recorded in 1992, and according to the Elias Sports Bureau, it's the Reds' longest streak to begin a season with only five starters since the 1898 team made every start through 147 games.
"It says something about them, how they've taken care of themselves and the fact that they're younger," said Reds manager Dusty Baker. "They're more experienced than most at their age. They train hard. Our medical staff and fitness people hopefully have found a formula on each one's workload -- training-wise, fitness-wise and how we've tried to use them. You can tell lately that it's the time of year where we can stretch them out a little more."
Padres: Alonso also facing former club
Volquez won't be the only former Reds player suiting up for San Diego on Thursday, as one-time Cincinnati prospect Yonder Alonso also will face his former club.
The Reds drafted Alonso with the seventh overall pick of the 2008 MLB Draft, but he only played 69 games in Cincinnati, sitting behind Joey Votto at first base.
This past offseason, Alonso was traded to the Padres along with Volquez, Yasmani Grandal and Brad Boxberger for Latos.
Alonso has played in 79 games for San Diego, hitting .257 with 18 doubles and 22 RBIs in 280 at-bats.
"I'm just trying to get my hits, man," Alonso said when asked about facing his former squad.
Padres manager Bud Black said he's been pleased with Alonso's progress so far and said he sees a bright future for his rookie first baseman.
"It's good for Yonder to get the Major League exposure often and regularly," Black said. "This guy has just over 300 Major League at-bats, not very many, so every at-bat is good for him. We are giving him an opportunity to see what he can do."
With the Reds loss and the Pirates win Wednesday, Cincinnati ended its 41-day span of holding at least a share of the division lead in the National League Central.