Buffalo Bills Pro Bowl defensive end Mario Williams and standout linebacker Kiko Alonso had hip surgery this offseason and remain sidelined at practice this week.
"We knew that we got [the procedure] done right away so he wouldn't miss any time," coach Doug Marrone told reporters. "We're just being progressive as we work this through camp with him."
Williams recorded 13 sacks last season.
Alonso ranked second in Associated Press Defensive Rookie of the Year balloting.
Several other players were sidelined, including wide receiver Robert Woods, who had ankle surgery.
Follow me on Twitter: @RavensInsider
Aaron Wilson covers the Ravens for The Baltimore Sun
Check out our partners at TiqIQ for the best deals on all games on the 2014 NFL schedule.
SEP 17 Jesse Lawrence
Jesse Lawrence of TiqIQ takes a look at the hot tickets this weekend.
SEP 16 Joel Corry
After registering 19 sacks in 2013, the St. Louis pass rusher cashes in big.
SEP 16 Jeff Fedotin
First-place squad could start 5-0.