The NFL suspended free-agent defensive backs Tom Zbikowski and Brandon McDonald on Tuesday, USA Today reported.
Zbikowski was suspended four weeks for violating the NFL's policy on performance-enhancing substances and Brandon McDonald for two weeks for violating the league's personal conduct policy.
Zbikowski, 28, was released by the Chicago Bears on Aug. 26. McDonald, 28, has been out of the NFL since March when his contract expired with the Tampa Bay Buccaneers.
The suspensions begin immediately and run while both players are free agents. Zbikowski could sign and play for a team in Week 6 and McDonald in Week 4.
Zbikowski has played in 64 games and started 25 in five seasons with the Baltimore Ravens and Indianapolis Colts. McDonald has appeared in 80 games and started 31 in six seasons with the Cleveland Browns, Arizona Cardinals, Detroit Lions and Buccaneers.