The following discovery won't rank right up there with the T formation, but it will have to do in these dog days of the NFL. Basic Principle for Week 10: the longer the season drags on, the more TV announcers come to resemble certain teams and players.

If the 49ers are hot and the Raiders are cold, take a look at CBS's John Madden on one hand and Roger Staubach on the other. If decrepit Craig Morton is making yet another comeback, how about CBS's Lindsey Nelson? And if the Colts are bad, can NBC's duo of Mike Adamle and Jim Turner be far behind?

The only announcer without a mirror image of himself is ABC's Howard Cosell. No player tells you how good he is and then goes zero for the season.

Without further ado, we bring you our "1981 Guide to NFL Announcers," being a totally subjective survey of who should be all-pro and who should be announcing for the Pottstown Firebirds.

Mike Adamle (NBC) -- His first season on play-by-play, and it shows. He reminds you of Vince Evans of the Bears: talent drowning amid its own mistakes. His fractured syntax (the Orange Bowl does not "filter out of human beings") can be funny, and he openly roots for the Jets. But he's a quick study. Stay tuned.

George Allen (CBS) -- He might be more useful to the network at Green Bay than in the booth. His big thing is to make the same observation (David Woodley's passes being hard to catch, for example, because the nose of the ball is pointed down) about a dozen times a game. Hard to listen to after the first quarter. No humor, all Xs and Os, all-Pottstown.

John Brodie (NBC) -- Like the Falcons, he gets stronger each year. He used to be Exhibit A of the tongue-tied ex-jock, but now ranks just below the best analysts. Could be more articulate, but with today's crop of analysts, we shouldn't get greedy.

Tom Brookshier (CBS) -- A success in his new play-by-play job. He opted for bad jokes and hearty laughs over blind-side hits as the network's No. 1 color man, so was bumped by Madden. Now he's more serious and seems better prepared. Big plus: he loosens up Roger Staubach, which is like loosening up Lon Chaney.

Howard Cosell (ABC) -- Here we go again. Better than on baseball, worse than on boxing. Quite frankly, a front-runner. Last Monday, he held his peace on Bronco Coach Dan Reeves' decision to go for a touchdown instead of a field goal. Never mind that Fran Tarkenton debated Reeves' decision before the play. Cosell waited until it succeeded before shouting: "It was the only way to go!" But give Howard this: no one makes halftime highlights as exciting.

Bob Costas (NBC) -- A blue-streak Walter Payton of a talker, he simply exhausts the listener. Good voice, always gives you the nuts and bolts on play-by-play. But, please, just a little breather on the chatter?

Don Criqui (NBC) -- His problem, say the networks: you can shoot the TWA ads 10 times but you can't do that with play-by-play. Lots of mistakes on yardage, player identifications and the like. Still, he wears well and doesn't intrude. A far sight better than, say, Costas, Jay Randolph (NBC) or Tim Ryan (CBS).

Dick Enberg (NBC) -- As consistent and able as anyone in play-by-play, and getting better every year. He religiously obeys what's known in the trade as the "Ohlmeyer Edict" -- a supposed order from NBC's executive producer for less talk and gushing. Enberg's a sensitive man whose personality comes across on the air.

Frank Gifford (ABC) -- A tad behind Enberg, but excellent, nonetheless. After 11 years in the "Monday Night Football" zoo, he can remain calm when Cosell and the Danderoo start pawing at each other. After getting ragged last year, the Giffer cut down on his mistakes. He's likable. You'd have him over for dinner.

John Madden (CBS) -- A huge success because he's a real person and talks to the man on the street. Irreverent, insightful, unpredictable, funny, down-to-earth. He talks to you one to one, as though you're sitting across from him at a lunch counter. Comes up with outrageous sound effects. Who else would break into a play-by-play and say: "Hey, Pat, look at Septien! He's got a mouthpiece in!"

Don Meredith (ABC) -- The Bert Jones of the booth: a superstar whose aura has started to fade. Still entertaining, still a terrific foil for Cosell if you're more interested in the show than the game. But the Danderoo seems to have run out of fresh anecdotes. He used to know all the players. Now he knows only Randy Rasmussen. Has the game passed him by?

Lindsey Nelson (CBS) -- Pure, pure announcer. Always gives you the down, yardage and time of possession. Not an entertainer but pleasant, businesslike and as optimistic as a baby doctor. He's been around as long as Dr. Spock, too. Being his sidekick, George Allen can't help but improve.

Vin Scully (CBS) -- The Ken Anderson of the airwaves: constantly overrated. Scully may be the finest baseball announcer in history, but he doesn't know football. He compensates with statistics and imagery. He probably would be fine doing football on radio. But we come to watch football on TV, not to hear the play-by-play man's prose and poetry.

Roger Staubach (CBS) -- He rarely tells us a thing. All the catches are "fine" and "outstanding." You hear few anecdotes about what it was like when he played or what emotions the quarterback may be feeling. Better with Brookshier, but still too stiff. Yea, Pottstown?

Merlin Olsen (NBC) -- "Father Murphy" of TV fantasy is handling only a half-season of games with Dick Enberg, and that's a sad confession. Olsen was the No. 1 analyst in football until this season, when Madden tied him. He oozes intelligence and uses replays almost as a teaching tool. So what if he doesn't crack jokes?

Hank Stram (CBS) -- Has an uncanny knack of reducing the game to understandable terms, although Madden can do this, too, with more humor. He was better in recent years when not teamed with Scully, who doesn't draw Stram out. Very straight and technical, he might be superb if teamed with Brookshier.

Pat Summerall (CBS) -- The Tom Landry of announcers. Cool, restrained, intelligent. He always remembers that TV is a visual medium in which brevity of speech is a virtue. If he were a doctor telling you the worst, he'd be so reassuring that everything would be all right. True value in commercial and on the air.

Fran Tarkenton (ABC) -- Like Steve Grogan, he's gone downhill for two years now. He's by no means ready for the Virginia Sailors, but how about Baltimore Colts preseason? There's an awful severity in his tone. He has a compulsion for predicting each play before it happens. And if they're going to announce the penalties in 20 seconds, anyway, why guess at them?

Bob Trumpy (NBC) -- He seemed in orbit last year, but when he recently was seen in Washington he fell smack into a crater. He gave us wrong explanations and "insights," such as how important special teams are. Chief asset: absolute candor. Liability: impulsiveness. So far, an enigma.

Jim Turner (NBC) -- Pottstown, make room. Here's a charter member of the Cliche-of-the-Month Club. Turner talks about teams that have their "backs to the wall" while "flirting with disaster." Meanwhile, the other team is "going to bend." But it's not, he warns, "going to break." He may be the one announcer you'd trade in for that ridiculous conductor who goes "Yyyyyyyyeeeees!" in the McDonald's commercial.