The other 25 semifinalists are offensive lineman Larry Allen, place kicker Morten Andersen, defensive back Steve Atwater, receiver Tim Brown, receiver Cris Carter, coach Don Coryell, running back Roger Craig, running back Terrell Davis, owner Ed DeBartolo, Jr., defensive lineman Charles Haley, offensive lineman Joe Jacoby, defensive back Albert Lewis, defensive back John Lynch, linebacker Karl Mecklenburg, owner Art Modell, offensive lineman Jonathan Ogden, coach Bill Parcells, receiver Andre Reed, defensive lineman Warren Sapp, offensive lineman Will Shields, defensive lineman Michael Strahan, commissioner Paul Tagliabue, special teams/receiver Steve Tasker, defensive back Aeneas Williams and general manager George Young.
The list of 27 semifinalists will be pared down to 15 finalists in January. Usually there are 25 semifinalists, but a three-way tie for the final position led to the two additional entries.
The seniors committee nominees, who were announced in August, are former Kansas City, Houston and Detroit defensive tackle Curley Culp and former Green Bay and Washington linebacker Dave Robinson.
The 2013 Hall of Fame class will be announced Feb. 2, the day before the Super Bowl.
Bettis played with the Los Angeles/St. Louis Rams from 1993-95 and for the Steelers from 1996-2005. He rushed for 13,662 yards and 91 touchdowns, was voted All-Pro twice and played in six Pro Bowls.
Greene, a linebacker, played for the Rams from '85-92 before joining the Steelers for three years. He later played for the Carolina Panthers and San Francisco 49ers.
Greene twice led the NFL in sacks, including the '94 season when he was with the Steelers. He was voted All-Pro twice and played in five Pro Bowls.
Steelers quarterback Ben Roethlisberger will not play against the Ravens. Roethlisberger will miss a third consecutive game with shoulder and rib injuries.
Third-stringer Charlie Batch will make a second consecutive start at quarterback. He threw three interceptions in Sunday's 20-14 loss at Cleveland.
Offensive tackle Mike Adams (ankle), backup quarterback Byron Leftwich (ribs) and linebacker LaMarr Woodley (ankle) also will not play.
Wide Receiver Jerricho Cotchery (ribs) is listed as questionable.
Receiver Antonio Brown (ankle), defensive lineman Casey Hampton (illness), safety Troy Polamalu (calf) and tackle Max Starks (back) are probable.
Polamalu is expected to play for the first time since the Oct. 7 home game against the Eagles. He has missed the past seven games.