Ratliff's debut coincides with the likely return of defensive tackle Stephen Paea, who missed last week's game at St. Louis due to a turf toe injury.
Both defensive linemen took repetitions at practice Thursday, and could be key in helping the Bears shore up a defense which ranks 31st against the run and is preparing to face Vikings running back Adrian Peterson.
"Right now, that's the plan [to play on Sunday]," Ratliff said. "I'm just eager to play football period. Stopping the run, that's part of our jobs. I full embrace that role and look forward to doing it."
A four-time Pro Bowler, Ratliff last played on Nov. 18 of last season as a member of the Dallas Cowboys. In that outing, Ratliff, 32, suffered a groin injury that led to a December sports hernia surgery.
The Bears signed Ratliff on Nov. 4, and the expectation was that he'd be ready to play in two to four weeks. The team's medical staff worked with Ratliff on rehabilitating, and as the days passed, the coaching staff gradually worked the defensive tackle into the lineup.
"It's been great here," Ratliff said. "It's a different atmosphere, good change of pace. I feel like myself again; feel pretty good. I just miss battling, period. Simply put, there's nothing really to elaborate on. You're a D-lineman. That's what you look forward to."
Surely Chicago's defense also looks forward to a return to the days the group could consistently stop the run. The Bears are coming off a horrid performance at St. Louis in which they allowed 258 yards rushing, and an average of 8.9 yards per attempt.
On the season, the Bears have allowed 48 runs for gains of 10 yards or more, including 10 runs for gains of 25 yards or more.
"He's in line to go," Bears coach Marc Trestman said. "We'll see what tomorrow brings, but he got reps today. He hasn't played for a while, so we don't have high expectations right now."
But even a mediocre performance from Ratliff, paired with Paea, could pay dividends Sunday against Peterson.
"When I'm in there, they trust that I'll be able to do my job," Paea said. "There's no supernatural running backs unless we're talking about Adrian Peterson. But going into this week, everybody's got to stay in their gaps, and make the tackles. If we're being disciplined and staying in our gaps, there's nowhere Adrian Peterson is gonna run unless he's gonna hurdle over our heads and start running."
In other injury news, running back Matt Forte returned to practice Thursday after missing Wednesday's work because of a hyperextended right knee. Forte worked in a limited capacity, but Trestman expects him to play Sunday against the Vikings.
"Practice today felt good," Forte said.
Receiver Brandon Marshall (quadriceps), and cornerback Derrick Martin (hamstring) also worked in a limited capacity at Thursday's practice, while safety Anthony Walters missed his second consecutive workout due to a groin injury. Marshall's injury shouldn't keep him out of Sunday's game, and Martin is also expected to play.