LAKE FOREST, Ill. – Competition for starting jobs at several key positions on offense will highlight this summer’s Bears training camp, which kicks off Wednesday with a 3 p.m. practice at Olivet Nazarene University in Bourbonnais.

After performing well late last season, Kyle Orton will compete with Rex Grossman for the Bears' starting quarterback position.

Center Olin Kreutz, right guard Roberto Garza, right tackle John Tait, tight end Desmond Clark and fullback Jason McKie are the only established starters on a unit that ranked 27th in the NFL in total yards, 30th in rushing and 29th in third-down efficiency last season.

That leaves quarterback, running back, both receiver positions, left tackle and left guard as jobs to be filled this summer, which should make for an interesting training camp and preseason.

The marquee competition, of course, is at quarterback where Rex Grossman and Kyle Orton will battle to lead the offense. Both showed flashes late last year and are entering their fourth season in coordinator Ron Turner’s system.

Grossman was benched after starting the first three games last season, but he performed much better in five contests after regaining the No. 1 job from Brian Griese.

The 2003 first-round pick passed for 913 yards with 3 touchdowns, 1 interception and an 80.2 passer rating in his second stint before sustaining a season-ending knee injury in a Week 14 loss in Washington. It was a vast improvement after he threw for 500 yards with 1 TD, 6 interceptions and a 45.2 passer rating in the first three games.

Grossman’s knee injury gave Orton a chance to play for the first time in nearly two years. The 2005 fourth-round pick started the final three games, completing 43 of 80 passes for 478 yards with 3 TDs, 2 interceptions and a 73.9 passer rating as the Bears lost to the Vikings before closing 2007 with back-to-back victories over the Packers and Saints.

Grossman and Orton will continue to alternate with the No. 1 offense on a daily basis as they did throughout offseason workouts. With the Bears wanting to evaluate how the quarterbacks perform against live defenses, the competition likely will extend well into the preseason.

Two other key players to watch in training camp are left tackle Chris Williams and running back Matt Forte. The Bears’ top two draft picks are expected to start as rookies after impressing coaches with their talent and ability to grasp the offense throughout the offseason.

Forte excelled in OTA and minicamp workouts, displaying fluid speed and quickness as a ballcarrier and receiver out of the backfield. The second-round pick arrives after rushing for 2,127 yards as a senior at Tulane, the seventh highest single-season total in NCAA history.

Veteran safety Mike Brown returns from a knee injury to anchor the Bears secondary.

Forte will be challenged by reliable veteran Adrian Peterson and recent free-agent acquisition Kevin Jones, a former Lions star who is trying to rebound from a torn ACL.

The receiver position is wide open entering training camp with Devin Hester, Marty Booker, Rashied Davis, Mark Bradley, Brandon Lloyd and third-round pick Earl Bennett among those vying to replace departed starters Muhsin Muhammad and Bernard Berrian.

Hester is determined to emerge as the No. 1 receiver after catching 20 passes for 299 yards and 2 TDs in limited action last season. Turner said in June that the Bears intend to triple Hester’s workload from an average of 10-12 snaps per game in 2007 to 30-35 this year.

Defensively, the Bears enter training camp trying to put a once dominant unit back together after it was decimated by injuries in the secondary and at tackle last season. Safety Mike Brown and cornerback Nathan Vasher are back after combining to miss 27 of 32 games.

After ranking second in the NFL in 2005 and fifth in 2006, the defense plummeted to 28th last season. But after re-signing perennial Pro Bowlers Brian Urlacher, Lance Briggs and Tommie Harris to new contracts this offseason, expectations are high entering camp.

Coach Lovie Smith will attempt to direct the Bears from worst-to-first in the NFC North just as he did in 2005 when Chicago won the first of two straight division championships. With players due to report to Bourbonnais by midnight Wednesday, that quest begins immediately.