St. Louis, MO -- (Sports Network) - St. Louis Rams running back Steven Jackson will miss next Sunday's game against the Chicago Bears with a thigh injury, while offensive tackle Orlando Pace will be out 2-to-4 weeks with a knee injury.

Jackson has missed the last two games and will miss his fourth game in five weeks. Rams head coach Jim Haslett said the running back just needs time to rest.

"He has had a second opinion (on the thigh injury)," said Haslett. "He has a strain with a little bit of blood in it, and it is going to take some time to heal," Haslett said. "(The doctor) thought that he should take some time off and let it heal and rest. (He) will be out this week."

Jackson was hurt during the October 19 game against Dallas, despite rushing for 160 yards and three touchdowns, then missed the following week's contest against New England. He returned against Arizona on November 2 after being limited in practice and managed just 17 yards on seven carries.

For the season, Jackson has 525 yards on 128 carries with four touchdowns and has added 25 catches for 259 yards.

Pace, the top overall pick of the 1997 draft, suffered an MCL injury that will keep him sidelined for the next few weeks and possibly for the rest of the season.

"(Putting Pace on injured reserve) is something that we will have to discuss," Haslett said. "Right now he is (out for) 2-to-4 (weeks) so I am going to talk to Orlando and see what he thinks."

Pace has played in all but one game this season after playing in just nine total games the past two years. The Ohio State product missed just nine games in his first nine seasons and has been to the Pro Bowl seven times, as well as being a first-team All Pro three times in his career.