| Last updated: Thu, July 9, 2009, 14:54 EDT |
| Date | Player | Pos. | Transaction |
| 7/7 | Robert Manuel | | Called Up from Minors |
| 7/7 | Drew Sutton | SS | Sent to Minors |
| 7/3 | Edwin Encarnacion | 3B | Removed From 60-Day DL, (Left wrist fracture) |
| 7/3 | Edwin Encarnacion | 3B | Recalled From Minors, Rehab Assignment |
| 7/3 | Danny Richar | 2B | Placed on 15-Day DL, (Torn labrum, left shoulder) |
| 7/1 | Drew Sutton | SS | Called Up from Minors |
| 7/1 | Jared Burton | P | Sent to Minors |
| 6/27 | Homer Bailey | P | Called Up from Minors |
| 6/27 | Adam Rosales | 3B | Sent to Minors |
| 6/26 | Corky Miller | C | Traded From, Chi. White Sox (for OF Norris Hopper) |
| 6/23 | Joey Votto | 1B | Recalled From Minors, Rehab Assignment |
| 6/23 | Wilkin Castillo | C | Placed on 15-Day DL, (Torn labrum, right shoulder) |
| 6/23 | Joey Votto | 1B | Removed From 15-Day DL, (Stress-related issues) |
| 6/21 | Edwin Encarnacion | 3B | Sent to Minors, For Rehabilitation |
| 6/20 | Danny Richar | 2B | Purchased From Minors |
| 6/20 | Matt Maloney | P | Sent to Minors |
| 6/20 | Alex Gonzalez | SS | Placed on 15-Day DL, (Bone chips in right elbow, out 4-5 weeks) |
| 6/20 | Edwin Encarnacion | 3B | Transferred to 60-Day DL, (Left wrist fracture) |
| 6/20 | Wilkin Castillo | C | Called Up from Minors |
| 6/18 | Joey Votto | 1B | Sent to Minors, For Rehabilitation |
| 6/17 | Mike Lincoln | P | Placed on 15-Day DL, (Bulging disc in neck) |
| 6/17 | Josh Roenicke | P | Called Up from Minors |
| 6/6 | Wilkin Castillo | C | Sent to Minors |
| 6/6 | Matt Maloney | P | Called Up from Minors |
| 6/2 | Jared Burton | P | Called Up from Minors |
| 6/2 | Edinson Volquez | P | Placed on 15-Day DL, (Right elbow tendinitis) |
| 6/1 | Jared Burton | P | Sent to Minors |
| 6/1 | Edinson Volquez | P | Removed From 15-Day DL, (Back spasms) |
| 5/30 | Joey Votto | 1B | Placed on 15-Day DL, (Stress-related issues) |
| 5/30 | Wilkin Castillo | C | Called Up from Minors |
| 5/26 | Wilkin Castillo | C | Sent to Minors |
| 5/26 | Nick Masset | P | Removed From 15-Day DL, (Strained left oblique) |
| 5/26 | Darnell McDonald | CF | Outrighted to Minors |
| 5/24 | Homer Bailey | P | Sent to Minors |
| 5/24 | Wilkin Castillo | C | Called Up from Minors |
| 5/23 | Justin Lehr | P | Traded From, Philadelphia (for cash considerations) |
| 5/22 | Ramon Ramirez | P | Sent to Minors |
| 5/22 | Darnell McDonald | CF | Designated for Assignment |
| 5/22 | Carlos Fisher | P | Called Up from Minors |
| 5/22 | Homer Bailey | P | Called Up from Minors |
| 5/22 | Edinson Volquez | P | Placed on 15-Day DL, (Back spasms) |
| 5/22 | Jonny Gomes | RF | Purchased From Minors |
| 5/19 | Ramon Ramirez | P | Called Up from Minors |
| 5/19 | Nick Masset | P | Placed on 15-Day DL, (Strained left oblique) |
| 4/28 | Adam Rosales | SS | Called Up from Minors |
| 4/28 | Edwin Encarnacion | 3B | Placed on 15-Day DL, (Left wrist fracture) |
| 4/16 | Danny Richar | 2B | Outrighted to Minors |
| 4/16 | Danny Richar | 2B | Called Up from Minors, - Not to Report |
| 4/6 | Laynce Nix | CF | Purchased From Minors |
| 4/5 | Adam Rosales | SS | Sent to Minors |
| 4/5 | Darnell McDonald | RF | Purchased From Minors |
| 4/5 | Wilkin Castillo | C | Sent to Minors |
| 4/5 | Bill Bray | P | Sent to Minors |
| 4/5 | Homer Bailey | P | Sent to Minors |
| 4/2 | Norris Hopper | CF | Outrighted to Minors |
| 3/31 | Josh Roenicke | P | Sent to Minors |
| 3/30 | Daryl Thompson | P | Sent to Minors |
| 3/30 | Norris Hopper | CF | Designated for Assignment |
| 3/23 | Daryle Ward | LF | Released |
| 3/23 | Danny Richar | 2B | Sent to Minors |
| 3/23 | Ramon Ramirez | P | Sent to Minors |
| 3/23 | Aaron Fultz | P | Released |
| 2/26 | Ron Flores | P | Signed to a Minor League Contract |
| 2/17 | Edwin Encarnacion | 3B | Signed, ( 2009-2010)(two-year contract, avoids arbitration) |
| 2/5 | Daryle Ward | LF | Signed to a Minor League Contract |
| 2/5 | Jacque Jones | LF | Signed to a Minor League Contract |
| 2/2 | Humberto Cota | C | Signed to a Minor League Contract |
| 1/28 | David Weathers | P | Signed, ( 2009; Opt 2010)(avoids arbitration) |
| 1/19 | Jonny Gomes | DH | Signed to a Minor League Contract |
| More Transactions |
