Would CBS News hire Dustin Hoffman to review Dustin Hoffman's latest big-screen smash? Would it ring up Lee Iacocca to report on sagging car sales in Detroit? How about Alexander Haig on the latest from the Persian Gulf?

"Hello, gulf fans, this is Coach Alex Haig with my new weeknight highlights show, 'Ayatollah Sidelines.' "

In effect, having Haig cover Iran is what Channels 7 and 9 have been doing with sports for lo these many years. Joe Theismann's sudden departure from Channel 7 last week -- he walked away from a part-time TV career worth $40,000 a year -- highlighted a practice as old as local television itself. It's called checkbook journalism.

Before we get to Sugar Ray Leonard, Johan Cruyff and all the other TV "commentators" who have loaned their names to the 6 o'clock news for five- and six-figure prices, let's give Channel 7 a small bouquet. When it came to entertainment versus journalism on the sports side of the set, it chose journalism.

The Theismann Affair began two Fridays ago when Morris Siegel, a former Washington Star sports columnist, delivered a clearly labeled commentary saying that Theismann might be bumped as quarterback if the team lost two more games. Joe demurred. He appeared on the station the following Monday, said commentators like Siegel ought to scram, called the report false and then quit.

Sources say the honorable Theismann never played the bully, never gave Channel 7 a "Mo-goes-or-I-go" ultimatum. It was just too much to have to respond to attacks every week, Theismann said. "And also," he added this week, "with (the Siegel) situation arising as it did, it gave me an opportunity to leave the station and work more on football."

Having read the Theismann-Siegel tea leaves, a number of people feel that Joe never would have hiked over one commentary -- a relatively tame one at that. How many Redskins said, even to their wives in the dark of night, "We get our backsides beaten every week so Joe can rake in the TV money?" Was the supposed team leader just itching for an out?

"No, no, no to the entire assumption," Theismann said. "TV has never been divisive. I just wanted to devote more time to football."

Whatever Theismann's motives, you've got to admire Channel 7 for putting it straight to him from the start. No sooner had he grumbled about Siegel than news director Dow Smith said he was committed to Siegel as his sports commentator. Siegel could say whatever he pleased. Channel 7 would like Joe aboard, but the final decision was his.

Nothing against Theismann, but the feeling here is he never should have been aboard in the first place. You like him on Channel 7's "Good Morning Washington" at 9 a.m.? Fine. Let him interview child psychologists and the Galloping Gourmet. But putting him on sports is like stacking the deck. It's the principle of the thing.

The one station in town that generally has avoided using jocks on the news (it did use Chris Hanburger part-time last year) is Channel 4. It would rather put out more money for taped highlights than for on-air talent -- a fact that just happens to make George Michael's sports show the most complete in town.

"The point of checkbook journalism," Michael says, "is to make you look more authoritative; to make you look like you know what you're talking about. But after you've done promos with the guy, how can you say straight out that (Joe) Gibbs has neglected the special teams?"

Michael's barb obviously was directed at Channel 9, the all-time, all-Met champ at hiring star players and coaches for the 6 o'clock news. You need all the fingers of one hand to count the stars for this year alone.

Gibbs has his own pregame show at noon Sundays and appears live for a few minutes on Mondays during football season. His TV salary, according to sources: $36,000. Sugar Ray shows up for an occasional commentary before one of his own fights ($50,000 this year, $60,000 next). Johan Cruyff ($25,000) and Paul Cannell (somewhat less) appeared during soccer season.

Then there's the case of Sonny Jurgensen. Although he has improved markedly in four years on the air, his chief attribute as a sportscaster is still his name. And while he lends a certain expertise on Gibbs' show or on "Redskin Sidelines" Monday nights, he never asks as hard a question as Glenn Brenner. Jurgensen's salary, according to sources: $115,000 to $125,000 a year.

In case you haven't noticed, there's an elementary game being played in all this: keepaway.

Gibbs and the others can never appear live on a rival TV station. Even Theismann can't appear on a live newscast anywhere but Channel 7 for the rest of the year, seeing how it still holds "rights" to him. Perhaps the biggest problem is Leonard. He's been stockpiled in a sense. Before a fight, Brenner will interview him for an hour in his rec room. Michael and Channel 7's Tim Brant are lucky to get two minutes.

In the end, however, it's a question of credibility. Although Brenner rated A-plus for his tough questioning of Gibbs last Monday, Jurgensen came across as the Redskins' chief apologist. When you're paying Gibbs or any other jock to be part of the broadcasting team, the tendency is to celebrate or commiserate with him.

For any station that wants to keep its Sugar Ray, there's one way out: Truth in Packaging. Sure, put him on. Roll him right onto the set for entertainment's sake. But call it show biz, don't call it journalism.