The accident occurred with just four minutes left in practice.
Jack Sprague, Mike Skinner and Steve Park also were involved in the wreck.
There will be two 125-mile qualifying races on Thursday to determine the rest of the starting lineup for Sunday's Great American Race. Jeff Green and Dale Earnhardt, Jr., nailed down the first two spots on Monday.
Burton said he got caught in traffic after Jack Sprague collided with Mike Skinner.
"Sprague got into the side of Skinner and turned Skinner sideways," Burton said. "That got the track all blocked up, and there was nowhere for anybody to go. So everybody plowed into everybody."
Sadler credited the accident to a lack of common sense.
"The 4 car (of Skinner) was blending in, and I guess the 0 (of Sprague) didn't see him and just absolutely ran in the side of him. I don't know if he misjudged him or what was going on, but it's a shame to wreck a bunch of good cars on the straightaway.
"I mean, we're supposed to be professionals and using our heads, and they're out there running into the side of each other on the straightaway. There's not much common sense going on."
Sadler said having to switch to a back-up car would be a setback, noting that his primary car was among the fastest on the track Tuesday.
"I'm going to tell you what; that thing was a rocket," Sadler said. "We led just about the whole doggone practice. Every lap we were out there, we were pretty much in the front.
"I decided to drift to the back a little bit just to see what my car would do around a lot of turbulence. Right at that time, the wreck happened with four minutes left to go in practice.
"I don't know what happened. I just wish people would use their heads more. It's put us in a bad predicament. We're going to have to try to do the best we can to get around it. There's a long time until Sunday, so we'll see what happens."
Burton said he had a capable back-up car but that it wasn't ready for Sunday yet. He added that he can't afford to have any problems with the car, either.
"There's quite a bit of work that has to go on with the backup car to get it ready, but not a tremendous amount," Burton said. "The big problem is if you have a problem with this car, then what do you do? I don't know what we would do if that happens.
"We only have two cars. The 6 (of teammate Mark Martin) only has two cars. We're behind, and our shop, in particular, is behind, especially when the 16 car (of teammate Greg Biffle) came in. We just couldn't get as much work done, so the thing that we did was the three teams in that shop only built two speedway cars rather than three.
"So, we've got to get through (Wednesday) and the 125s and, hopefully, all the rest of practice because we don't have another car," Burton said. "We would figure something out, obviously, but I don't know what that would be."
Sadler said he has a third car that was to be delivered from his shop in Virginia on Wednesday.
"The guys are at the shop right now painting it," Sadler said. "They'll put it on the trailer tonight around midnight or so and bring it on down, so we do have a third car.
"That car isn't really as good as the other two, so I really have to be careful the rest of the week if I'm going to have any chance at the 500."
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