| Last updated: Tue, November 10, 2009, 14:32 EST |
| Date | Player | Pos. | Transaction |
| 11/9 | Darnell McDonald | CF | Refused Minor League Assignment - Free Agent |
| 11/9 | Wilkin Castillo | C | Outrighted to Minors |
| 11/9 | Wilkin Castillo | C | Removed From 60-Day DL, (Right shoulder surgery - out for season) |
| 11/6 | Justin Lehr | P | Outrighted to Minors |
| 11/5 | Corky Miller | C | Outrighted to Minors |
| 11/5 | Darnell McDonald | CF | Outrighted to Minors |
| 11/4 | Danny Richar | 2B | Removed From 60-Day DL, (Left shoulder surgery - out for season) |
| 11/4 | Danny Richar | 2B | Refused Minor League Assignment - Free Agent |
| 11/4 | Kevin Barker | 1B | Outrighted to Minors |
| 10/14 | Aaron Harang | P | Removed From 15-Day DL, (Appendectomy - out for season) |
| 9/30 | Chris Dickerson | LF | Removed From 15-Day DL, (Sprained left ankle) |
| 9/22 | Willy Taveras | CF | Removed From 15-Day DL, (Strained right quadriceps) |
| 9/19 | Ramon Hernandez | C | Removed From 15-Day DL, (Left knee surgery - out 4-6 weeks) |
| 9/15 | Laynce Nix | LF | Removed From 15-Day DL, (Bulging cervical disc) |
| 9/14 | Jay Bruce | RF | Recalled From Minors, Rehab Assignment |
| 9/14 | Juan Francisco | 3B | Called Up from Minors |
| 9/14 | Jay Bruce | RF | Removed From 15-Day DL, (Fractured right wrist) |
| 9/9 | Ryan Hanigan | C | Removed From 15-Day DL, (Concussion) |
| 9/9 | Ryan Hanigan | C | Recalled From Minors, Rehab Assignment |
| 9/8 | Matt Maloney | P | Called Up from Minors |
| 9/7 | Carlos Fisher | P | Called Up from Minors |
| 9/3 | Ryan Hanigan | C | Sent to Minors, For Rehabilitation |
| 9/3 | Jay Bruce | RF | Sent to Minors, For Rehabilitation |
| 9/2 | Danny Richar | 2B | Transferred to 60-Day DL, (Left shoulder surgery - out for season) |
| 9/2 | Pedro Viola | | Purchased From Minors |
| 8/31 | Johnny Cueto | P | Removed From 15-Day DL, (Right shoulder inflammation) |
| 8/31 | Laynce Nix | LF | Placed on 15-Day DL, (Bulging cervical disc) |
| 8/31 | Matt Maloney | P | Sent to Minors |
| 8/31 | Carlos Fisher | P | Sent to Minors |
| 8/31 | Ramon Ramirez | P | Called Up from Minors |
| 8/31 | Kevin Barker | 1B | Called Up from Minors |
| 8/29 | Matt Maloney | P | Called Up from Minors |
| 8/29 | Kevin Barker | 1B | Sent to Minors |
| 8/25 | Corky Miller | C | Purchased From Minors |
| 8/25 | Mike Lincoln | P | Transferred to 60-Day DL, (Bulging disc in neck) |
| 8/25 | Darnell McDonald | CF | Purchased From Minors |
| 8/25 | Lew Ford | LF | Signed to a Minor League Contract |
| 8/25 | Edinson Volquez | P | Transferred to 60-Day DL, (Right elbow surgery - out for season) |
| 8/24 | Chris Dickerson | LF | Placed on 15-Day DL, (Sprained left ankle) |
| 8/24 | Ryan Hanigan | C | Placed on 15-Day DL, (Concussion) |
| 8/23 | Scott Rolen | 3B | Removed From 15-Day DL, (Concussion) |
| 8/23 | Aaron Harang | P | Placed on 15-Day DL, (Appendectomy - out for season) |
| 8/23 | Scott Rolen | 3B | Recalled From Minors, Rehab Assignment |
| 8/20 | Scott Rolen | 3B | Sent to Minors, For Rehabilitation |
| 8/20 | Micah Owings | P | Removed From 15-Day DL, (Right shoulder tightness) |
| 8/20 | Johnny Cueto | P | Placed on 15-Day DL, (Right shoulder inflammation) |
| 8/20 | Micah Owings | P | Recalled From Minors, Rehab Assignment |
| 8/19 | Willy Taveras | CF | Placed on 15-Day DL, (Strained right quadriceps) |
| 8/19 | Drew Stubbs | CF | Purchased From Minors |
| 8/14 | Kevin Barker | 1B | Purchased From Minors |
| 8/11 | Scott Rolen | 3B | Placed on 15-Day DL, (Concussion) |
| 8/11 | Chris Dickerson | LF | Removed From 15-Day DL, (Bruised right rotator cuff) |
| 8/11 | Chris Dickerson | LF | Recalled From Minors, Rehab Assignment |
| 8/10 | Micah Owings | P | Sent to Minors, For Rehabilitation |
| 8/10 | Jared Burton | P | Removed From 15-Day DL, (Right shoulder fatigue) |
| 8/6 | Chris Dickerson | LF | Sent to Minors, For Rehabilitation |
| 7/31 | Scott Rolen | 3B | Traded From, Toronto (for 3B Edwin Encarnacion, 4-player deal) |
| 7/31 | Kip Wells | P | Purchased From Minors |
| 7/31 | Justin Lehr | P | Purchased From Minors |
| 7/29 | Wladimir Balentien | LF | Traded From, Seattle (for RHP Robert Manuel) |
| 7/27 | Drew Sutton | SS | Called Up from Minors |
| 7/27 | Robert Manuel | P | Called Up from Minors |
| 7/27 | Chris Dickerson | LF | Placed on 15-Day DL, (Bruised right rotator cuff) |
| 7/27 | Micah Owings | P | Placed on 15-Day DL, (Right shoulder tightness) |
| 7/26 | Jared Burton | P | Placed on 15-Day DL, (Right shoulder fatigue) |
| 7/26 | Josh Roenicke | P | Called Up from Minors |
| 7/24 | Alex Gonzalez | SS | Recalled From Minors, Rehab Assignment |
| 7/24 | Alex Gonzalez | SS | Removed From 15-Day DL, (Bone chips in right elbow, out 4-5 weeks) |
| 7/24 | Drew Sutton | SS | Sent to Minors |
| 7/20 | Jared Burton | P | Called Up from Minors |
| 7/20 | Alex Gonzalez | SS | Sent to Minors, For Rehabilitation |
| 7/20 | Ramon Hernandez | C | Placed on 15-Day DL, (Left knee surgery - out 4-6 weeks) |
| 7/20 | Robert Manuel | P | Sent to Minors |
| 7/20 | Craig Tatum | C | Called Up from Minors |
| 7/17 | Josh Roenicke | P | Sent to Minors |
| 7/17 | Drew Sutton | SS | Called Up from Minors |
| 7/12 | Jay Bruce | RF | Placed on 15-Day DL, (Fractured right wrist) |
| 7/12 | Adam Rosales | 3B | Called Up from Minors |
| 7/9 | Kip Wells | P | Signed to a Minor League Contract |
| 7/7 | Robert Manuel | P | 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 | Adam Rosales | 3B | Sent to Minors |
| 6/27 | Homer Bailey | P | Called Up from Minors |
| 6/26 | Corky Miller | C | Traded From, Chi. White Sox (for OF Norris Hopper) |
| 6/23 | Joey Votto | 1B | Removed From 15-Day DL, (Stress-related issues) |
| 6/23 | Wilkin Castillo | C | Placed on 15-Day DL, (Torn labrum, right shoulder) |
| 6/23 | Joey Votto | 1B | Recalled From Minors, Rehab Assignment |
| 6/21 | Edwin Encarnacion | 3B | Sent to Minors, For Rehabilitation |
| 6/20 | Danny Richar | 2B | Purchased From 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 |
| 6/20 | Matt Maloney | P | Sent to 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 | Edinson Volquez | P | Placed on 15-Day DL, (Right elbow tendinitis) |
| 6/2 | Jared Burton | P | Called Up from Minors |
| 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 | Darnell McDonald | CF | Outrighted to Minors |
| 5/26 | Nick Masset | P | Removed From 15-Day DL, (Strained left oblique) |
| 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 | Homer Bailey | P | Called Up from Minors |
| 5/22 | Carlos Fisher | P | Called Up from Minors |
| 5/22 | Jonny Gomes | RF | Purchased From Minors |
| 5/22 | Darnell McDonald | CF | Designated for Assignment |
| 5/22 | Ramon Ramirez | P | Sent to Minors |
| 5/22 | Edinson Volquez | P | Placed on 15-Day DL, (Back spasms) |
| 5/19 | Ramon Ramirez | P | Called Up from Minors |
| 5/19 | Nick Masset | P | Placed on 15-Day DL, (Strained left oblique) |
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