The Bears (6-4) enter Week 12 tied atop the NFC North with the Lions (6-4), one game ahead of the Packers (5-5). On Sunday, Detroit hosts Tampa Bay and Green Bay hosts Minnesota.
Appearing in the last four games, McCown has completed 61 of 101 passes for 754 yards with five touchdowns, no interceptions and a 100.0 passer rating that ranks seventh in the NFL among quarterbacks with at least 100 passing attempts.
McCown has appeared in four career games with two starts against the Rams, completing 43 of 68 passes for 515 yards with two TDs, no interceptions and a 96.1 passer rating.
The Rams (4-6) are coming off their bye week. They had lost three straight before stunning the Colts 38-8 in Indianapolis on Nov. 10. In that game, rookie Tavon Austin scored touchdowns on a 98-yard punt return and receptions of 57 and 81 yards.
The Rams defense is led by defensive end Robert Quinn, who ranks second in the NFL and first in the NFC with 12 sacks.
Sunday's game will feature a match-up between brothers, Bears rookie right guard
The Bears hold a 52-35-3 advantage in the all-time series between the teams, having won four straight after losing four in a row. Two of those victories came in St. Louis in 2006 and 2008.
The Bears won the last meeting 23-6 on Sept. 23, 2012 at Soldier Field. Chicago's defense generated six sacks and two takeaways, returned an intercepted for a touchdown, and held the Rams to a pair of Greg Zuerlein field goals.
In total yards, the Bears offense ranks 9th in the NFL (18th rushing and 10th passing), while the Rams defense ranks 19th (18th against the run and 14th versus the pass). The Bears defense is 24th overall (31st against the run and 17th versus the pass, while the Rams offense is 27th (22nd rushing and 21st passing).
ChicagoBears.com will provide all the latest Bears news throughout the week from Halas Hall. Coach Marc Trestman is scheduled to address the media Wednesday, Thursday and Friday. Defensive coordinator Mel Tucker and special teams coordinator Joe DeCamillis will be available Wednesday, while McCown and offensive coordinator Aaron Kromer will speak Thursday.