OWINGS MILLS, Md. -- The Baltimore Ravens fear they lost running back Gus Edwards and cornerback Marcus Peters to season-ending knee injuries Thursday, sources told ESPN's Adam Schefter.

The Ravens believe Edwards and Peters tore their ACLs during Thursday's practice, sources tell Schefter. Baltimore wasn't practicing in full pads Thursday. Both players are undergoing testing to confirm the initial diagnosis.

This continues a horrid run of injuries for Baltimore and delivers a major blow to the Ravens' Super Bowl aspirations.

Edwards becomes the third running back to suffer a season-ending injury in a span of 12 days. J.K. Dobbins tore the ACL in his left knee the preseason finale Aug. 28, and Justice Hill hurt an Achilles tendon Sept. 9.

Ty'Son Williams, a practice player from a year ago who doesn't have an NFL carry, becomes the Ravens' lead back. The other two running backs on the roster -- Trenton Cannon and Le'Veon Bell (practice squad) -- only started practicing with the Ravens on Wednesday.

The Ravens are also signing free agent running back Devonta Freeman to their practice squad on Thursday, his agent, Drew Rosenhaus, told Schefter. It is expected that Freeman will be promoted to the active roster.

The Ravens have had the NFL's most dominant ground attack, leading the league in rushing the past two seasons. Dobbins and Edwards totaled 1,528 yards rushing last season, which accounted for 81% of the output by Baltimore running backs. Edwards signed a three-year, $12.38 million deal in June that included $8 million in guaranteed money.

The loss of Peters would represent the most significant injury to the defense this year. The Ravens have depth at cornerback, but it will be difficult to replace Peters' playmaking ability. His 31 interceptions leads the NFL since he entered the league in 2015.

Since Peters was traded to Baltimore in Week 9 of 2019, the Ravens have allowed the fewest yards per pass attempt (6.1) and tied for the second-fewest touchdown passes allowed (31), according to ESPN Stats & Information.

Anthony Averett, a fourth-round pick in 2018, would be a candidate to replace Peters and start opposite Marlon Humphrey.

The Ravens open the season at the Las Vegas Raiders on Monday Night Football.