Joe Flacco put in a full practice last week to signal he is close to returning, but there won't be a quarterback controversy in Baltimore.
Harbaugh added his decision was based on giving the Ravens the best chance to win right now and the head coach complimented how Flacco has dealt with the situation.
"Listen, there's a very good chance we're going to need Joe Flacco and any other player in that role, a backup role, to win us a game," Harbaugh said.
The team's decision to stick with Jackson doesn't come as a big surprise when considering Jackson compiled a 3-1 record as a starter in Flacco's absence (because of a hip injury) to put the Ravens in postseason contention.
"I guess my overall thought about it is obviously disappointed that I can't be a part of this team in the same capacity that I have been for a longtime," Flacco said. "But, [I've] always gotta be ready and stay sharp and be ready for the call at any point."
Jackson also provided a dynamic piece to the offense with his legs over the past four games, rushing for 334 yards and two touchdowns on 68 carries.
In the meantime, where this leaves a healthy Flacco going forward remains the biggest question, as it is often said an injury shouldn't cause a starter to lose his job. Flacco led the Ravens to a championship in Super Bowl XLVII, where he was recognized as the MVP. The last few seasons, however, have been disappointments.