The three-time Pro Bowl wide receiver was limited in Friday's practice and listed as doubtful for this weekend's regular-season finale against the Cincinnati Bengals, just a little over one week after he had surgery to repair a torn meniscus in his knee.
The Ravens didn't reveal which knee Boldin injured.
At the time of Boldin's surgery, Ravens coach John Harbaugh said the 31-year-old receiver was expected to miss the rest of the regular season but return in time for the playoffs. But Boldin has progressed.
"Very encouraging," Harbaugh said of Boldin practicing, according to the team's official website.
"Those guys rehab hard. Anquan is a very tough guy. Marshal (Yanda) is a very tough guy. Cary (Williams) is very tough. Those guys are tough people. They want to do everything they can to play, and I think they are all doing everything they can to play as soon as they can."
Boldin was ruled out of last Saturday's victory over Cleveland Browns, the first time he has missed action since joining the Ravens at the start of the 2010 season. Boldin has 57 receptions for 887 yards and three touchdowns this season.
Up front, Yanda, a Pro Bowl guard, was listed as doubtful with a chest injury after limited participation in Friday's practice. He didn't practice Wednesday or Thursday.
"I felt OK out there today, so we'll see what happens come Sunday," Yanda told the team's website. "We'll see."
Williams, a cornerback, has been cleared to play after suffering a concussion last Sunday. He was listed as questionable after being limited in practice all week.
For a complete look at all injuries around the league, go to NFL.com's injury page.
The Associated Press contributed to this report.