| | | Friday, October 19th, 2012 | | 1B Eric Ware was designated for assignment and placed on waivers. |
| Sunday, October 7th, 2012 | | Placed CF Gary Hunter on the active roster. | | Activated CF Gary Hunter from the 60-day disabled list. |
| Monday, October 1st, 2012 | | SS Manny Valéncia was designated for assignment and placed on waivers. | | SS Craig Henderson was designated for assignment and placed on waivers. |
| Thursday, September 27th, 2012 | | Placed RF Roberto Mendoza on the 14-day disabled list, retroactive to 09/26/2012. |
| Friday, September 7th, 2012 | | Purchased the contract of RF Bill Watson from Triple A Antioch. |
| Tuesday, July 10th, 2012 | | Signed 1B Kieran Simmons to a 5-year contract extension worth a total of $25,000,000. |
| Thursday, June 28th, 2012 | | Signed SP Juan Rosado to a 3-year contract extension worth a total of $3,300,000. |
| Saturday, June 16th, 2012 | | Signed SS Wayne Massingham to a 3-year contract extension worth a total of $4,500,000. |
| Monday, May 7th, 2012 | | Signed C Artie Sanders to a 4-year contract extension worth a total of $30,000,000. |
| Thursday, April 26th, 2012 | | Activated RF Ken Wade from the disabled list. | | Sent RF Ken Wade to Triple A Antioch for injury rehab. |
| Sunday, April 15th, 2012 | | Placed SS José Sánchez on the 14-day disabled list, retroactive to 04/14/2012. | | Recalled 1B Daniel Hall from Triple A Antioch. |
| Tuesday, April 10th, 2012 | | Placed LF Tom Klein on the 14-day disabled list, retroactive to 04/09/2012. | | Recalled CF Chet Haynie from Triple A Antioch. |
| Sunday, April 8th, 2012 | | Placed CF Gary Hunter on the 14-day disabled list, retroactive to 04/07/2012. | | Recalled RF Bill Watson from Triple A Antioch. |
| Saturday, March 31st, 2012 | | Activated C Artie Sanders from the disabled list. |
| Sunday, March 25th, 2012 | | Placed RF Ken Wade on the 14-day disabled list, retroactive to 03/24/2012. |
| Saturday, March 24th, 2012 | | Placed SP Ray Lester on the 14-day disabled list, retroactive to 03/23/2012. |
| Monday, March 12th, 2012 | | Placed C Artie Sanders on the 14-day disabled list, retroactive to 03/11/2012. | | Purchased the contract of C Paul Johnson from Triple A Antioch. | | CF Cory Brown was designated for assignment, placed on waivers and taken off the 40-man roster. |
| Monday, February 20th, 2012 | | Signed C Haden Boyd to a 3-year contract extension worth a total of $7,200,000. |
| Friday, February 17th, 2012 | | Signed pitching coach Mike Martin to a 4-year, $570,000 per year contract. |
| Saturday, February 11th, 2012 | | Signed manager Will Keen to a 4-year, $590,000 per year contract. | | Signed hitting coach Allen Davis to a 4-year, $560,000 per year contract. |
| Thursday, February 9th, 2012 | | Signed bench coach Blair Fritz to a 3-year, $590,000 per year contract. |
| Sunday, February 5th, 2012 | | Signed SP Ray Larson to a 3-year contract extension worth a total of $6,000,000. |
| Thursday, February 2nd, 2012 | | Signed SP Brad Anderson to a 2-year contract extension worth a total of $4,800,000. | | Signed 2B Tonito Almonte to a 2-year contract extension worth a total of $2,800,000. |
| Friday, January 20th, 2012 | | Signed 1B Eric Ware to a 4-year contract extension worth a total of $77,400,000. |
| Wednesday, January 18th, 2012 | | Signed team doctor Tom Robinson to a 5-year, $430,000 per year contract. |
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