| Transactions | ||||||
| Date | Team | Player | Type | OthTm | EffDate | When |
| 3/15/1999 | CRH | Norton | Acquired via trade | GEO | After | |
| 3/15/1999 | CRH | Valentin | Traded away | GEO | After | |
| 6/11/1999 | TON | Gwynn | Traded away | WIZ | After | |
| 6/11/1999 | TON | Kotsay | Acquired via trade | WIZ | After | |
| 6/11/1999 | TON | Orosco | Traded away | WIZ | After | |
| 6/11/1999 | TON | Relaford | Acquired via trade | WIZ | After | |
| 6/11/1999 | WIZ | Gwynn | Acquired via trade | TON | After | |
| 6/11/1999 | WIZ | Kotsay | Traded away | TON | After | |
| 6/11/1999 | WIZ | Orosco | Acquired via trade | TON | After | |
| 6/11/1999 | WIZ | Relaford | Traded away | TON | After | |
| 6/12/1999 | TON | Nen | Promoted to active roster | Before | ||