CHICAGO (CBS) – One real fear for players this year is that the replacement refs out on the field are not experienced in the NFL.

That could lead to players getting hurt because the new refs are not experienced with the rules, critics say.

CBS 2’s Pamela jones spoke with a former referee who agrees.

“It would be like taking a doctor and sending him to medical school for three months and then putting him in as a brain surgeon,” says retired ref Jerry Markbreit, who officiated for 23 years with the NFL.

Markbreit, who resides in the suburbs, says using replacement refs is a bad call. The NFL has locked out regular refs because labor negotiations have broken down.

“It takes four or five years for a veteran collegiate official to become really proficient in the National Football League. Now, how could they possibly train them in three months?” he says.

In the ‘80s, Markbreit ejected Charles Martin for slamming the Bears’ Jim McMahon to the ground after a play — a tough call even for a veteran NFL ref.

“I don’t think the replacement ref would have been there to make the call,” Markbreit says.

The players have questions, too, like whether the replacement officials can keep up when the pace picks at the start of the regular season Sept. 15.

Experts say many of the replacement refs have officiated for college games. But the NFL rules are more intricate.

There was an NFL official on the sidelines of the Bears game Friday to help out when necessary.