BALTIMORE -- The Baltimore Ravens' starting defense closed out a perfect preseason in Saturday's 13-9 victory over the Buffalo Bills -- at least by scoreboard standards.

Terrell Suggs and the first-team defense didn't allow a point in nine drives this entire preseason, including four physically dominating ones against the Bills. Baltimore, which entered the game with the No. 1 defense in the preseason, isn't expected to play its starters in the preseason finale Thursday at New Orleans.

On Saturday night, the Ravens' starters held Buffalo to 31 yards on 11 plays, knocking quarterback Tyrod Taylor out of the game on a sack by linebacker Matthew Judon. Baltimore's first-team defense pushed the Bills around up front, finishing with as many quarterback hits (two) as first downs allowed.

Overall, the Ravens' starting defense forced punts on all nine drives this preseason, giving up a total of 74 yards against the Washington Redskins, Miami Dolphins and Bills. The farthest an offense drove on Baltimore's starters was the Ravens' 44-yard line.

QB depth chart: Ryan Mallett, who is filling in for the injured Joe Flacco (back), threw the ball better in this preseason game, but he still failed to consistently move the ball down the field. He completed 6 of 10 passes for 58 yards (15 of which came on a 15-yard pass on third-and-17). ... Josh Woodrum failed to capitalize on his first snaps with the starting offense this preseason and make a concerted run at the backup job. Woodrum, who finished 8-of-13 for 55 yards, did throw a touchdown pass to Taquan Mizzell in a tight window later in the game.

When it was starters vs. starters, the Ravens looked ...: like they have all preseason. The defense dominated, and the Flacco-less offense struggled to score. The starting defense forced punts on all four series against Buffalo. The offense managed only a 40-yard field goal, which was the result of good field position (it was a 25-yard scoring drive). The Ravens' running game continues to sputter. Terrance West managed 17 yards on five carries (3.4-yard average).

Brief scare with Justin Tucker: The Ravens held their breath for a while until the most accurate kicker in NFL history cleared the concussion protocol. Tucker put himself at risk in the first quarter, when he attempted to make a tackle on a kickoff that followed his 40-yard field goal. He put his head down in an attempt to stop Bills returner Brandon Tate, who was eventually pushed out of bounds. This came one week after Tucker received flak from teammates for trying to return a fumble off a kickoff for a touchdown.

One reason to be concerned: Penalties. The Ravens have drawn more flags as the preseason has progressed, and it contributed to the ugly third preseason game. In the first half, Baltimore had 110 penalty yards (on 10 penalties) and 114 yards of total offense.

Campanaro closing in on returner job: It's looking like Michael Campanaro will hold on to the punt returner job. He averaged 10.8 yards on four returns, including a runback of 17 yards. Campanaro's path became clearer when undrafted rookie Tim White suffered a season-ending thumb injury. Keenan Reynolds is behind Campanaro on the depth chart.

Rookie watch: Cornerback Jaylen Hill made his second interception of the preseason. The undrafted rookie out of Jacksonville State has great awareness and ball skills. It's going to be tough to keep him off the 53-man roster.

Injuries sideline 14 players: The Ravens remain short-handed this preseason as injuries kept out 16 percent of their roster. Baltimore was without Flacco, left tackle Ronnie Stanley (undisclosed), running back Danny Woodhead (hamstring), wide receiver Breshad Perriman (hamstring), cornerback Marlon Humphrey (hamstring), linebacker Albert McClellan (undisclosed), cornerback Brandon Boykin (undisclosed), linebacker Donald Payne (undisclosed) and offensive tackle Stephane Nembot (undisclosed). Tight end Maxx Williams (offseason knee surgery) was likely held out as a precautionary measure. Baltimore has four other players who will start the season on injured reserve: running back Kenneth Dixon (knee), cornerback Maurice Canady (knee), offensive lineman Nico Siragusa (knee) and receiver-returner Tim White (thumb).