Eberflus said Fields and select starters would not play in Chicago's second preseason game due to the amount of "invaluable" work the first-team units got during joint practices this week with the Colts.
"[Fields is] not playing. And the selected starters that we have are not playing in the game because of the work we've done here," Eberflus said at the Grand Park Sports Campus. "We decided that last night, and that's what we're going with. We have a lot of great opportunity. I talked to the backups just now and last night about the opportunity they have ahead of them getting all these reps."
Fields played seven snaps in Chicago's 23-17 preseason win over the Tennessee Titans and went 3-for-3 for 129 yards and two touchdowns, both of which came on passes behind the line of scrimmage that wide receiver DJ Moore and running back Khalil Herbert took 50-plus yards to the end zone.
Eberflus said the Bears have not discussed whether Fields would play in Chicago's preseason finale against the Buffalo Bills at Soldier Field on Aug. 26.
"The joint practices, that's not something that we'll always do," Eberflus said. "I can't say that. But it's something we're doing this year. That's what we thought was best for our football team at this time, and then we will discuss the third game going forward. We got a bunch of good practices next week against each other heading into that Buffalo week. We'll decide at the latter part of that week what's going to happen."
On Monday, Eberflus said he wanted to see Fields get "more action" during the week and came away pleased with the quarterback's progress through three weeks of training camp.
"I think he's right on pace," Eberflus said. "He was 8-for-8 and had four touchdowns in 7-on-7 [on Thursday], that was excellent. Rhythm, timing, he's getting better there. Sometimes it's a protection breakdown. It's always everybody. It's the other 10 guys that need to operate. Are we running the routes correctly? Are we protecting him the right way, giving him time? And doing those types of things it takes to have an efficient passing game."
Injuries affected the strength of Fields' pass protection Thursday. Projected starting right guard Nate Davis, who was in pads for only the second time during training camp, is in a ramp-up period from an undisclosed injury. Second-year offensive lineman Ja'Tyre Carter spent most of the team periods working at right guard with the first-team offensive line.
Center Cody Whitehair sustained an injury to his right hand during one-on-one drills and was replaced by Doug Kramer. Eberflus did not have an update on the severity of Whitehair's injury but noted that both safety Eddie Jackson and wide receiver Velus Jones Jr., who were absent from practice Thursday, are dealing with injuries not considered "long-term."
Thursday's up-and-down practice for the Bears offense finished with Fields completing three passes during the move-the-ball period against the Colts' first-team defense.