| Date | Player | Position | Transaction |
|---|---|---|---|
| May 19 | Brody Eldridge | TE | Acquired from waiver |
| May 18 | Jose Valdez | ROT | Acquired from waiver |
| May 15 | Barry Richardson | T | Signed/unrest FA |
| May 15 | Mario Haggan | LB | Signed/unrest FA |
| May 11 | Marquis Johnson | CB | Signed by St. Louis |
| May 10 | Jamie Childers | TE | Signed by St. Louis |
| May 8 | Sammy Brown | LB | Signed by St. Louis |
| May 8 | Todd Anderson | RB | Signed by St. Louis |
| May 8 | Jeremy Caldwell | CB | Signed by St. Louis |
| May 8 | Derrick Choice | LB | Signed by St. Louis |
| May 8 | Matt Conrath | DT | Signed by St. Louis |
| May 8 | Matt Daniels | S | Signed by St. Louis |
| May 8 | Austin Davis | QB | Signed by St. Louis |
| May 8 | Cory Harkey | TE | Signed by St. Louis |
| May 8 | Michael Hay | G | Signed by St. Louis |
| May 8 | T. Bob Hebert | C | Signed by St. Louis |
| May 8 | Johnny Hekker | P | Signed by St. Louis |
| May 8 | Alex Hoffman-Ellis | LB | Signed by St. Louis |
| May 8 | Jamaar Jarrett | DE | Signed by St. Louis |
| May 8 | Nicholas Johnson | WR | Signed by St. Louis |
| May 8 | Noah Keller | LB | Signed by St. Louis |
| May 8 | Rodney McLeod | S | Signed by St. Louis |
| May 8 | Calvin Middleton | RB | Signed by St. Louis |
| May 8 | Deangelo Peterson | TE | Signed by St. Louis |
| May 8 | Quinton Pointer | S | Signed by St. Louis |
| May 8 | Nick Schwieger | RB | Signed by St. Louis |
| May 8 | Scott Smith | DE | Signed by St. Louis |
| May 8 | Travis Tripucka | LB | Signed by St. Louis |
| May 8 | Joe Long | T | Signed by St. Louis |
| May 4 | Gary Gibson | DT | Signed/unrest FA by St. Louis (Two-year contract (through 2013)) |
| May 4 | Thomas Welch | LOT | Acquired from waiver by St. Louis |
| May 3 | Dominique Curry | SPTM | Cut by St. Louis |
| May 3 | Marquis Johnson | CB | Cut by St. Louis |
| May 3 | Brian Jackson | CB | Cut by St. Louis |
| May 3 | Thomas Welch | LOT | Cut by St. Louis |
| May 2 | Josh Brown | KFG/KKO | Signed by St. Louis |
| May 1 | Jermelle Cudjo | RDT | Re-signed/excl. FA by St. Louis |