The concept of the relief pitcher is as old as baseball itself. The originals having been introduced sometime in the early ‘80s -- that would be the 1880s, old Sport.

For a couple of generations they were just washed up starters used to mop up one-sided games. The notion that you should call upon a young, fresh arm to bail out your mighty ace at the end of a tight or vital game was considered anathema.

Nowadays, relievers are baseball’s hottest commodities. No team features fewer than six and better teams may have eight, all varying in the look, stuff, and purpose they present. There are relievers for all occasions, all situations. They parade through game after game, often asked to throw just a dozen pitches, sometimes merely three or four. But they must be on call at least every other day, ready to fire every pitch as if it were their last; and sometimes, it is.

Relief pitchers have profoundly changed baseball and it has come to the point where they dominate it, for better or worse. A fair number of we who merely stand by and watch might vote the latter.

It was John J. McGraw, fierce and legendary skipper of the pre-war New York Giants’ firewagon (that would be WWI, old Sport) who refined the role. He had a pitching staff to die for, anchored by the incomparable Christy Mathewson and his colorful sidekick, Rube Marquard, with their gilded services being nicely supplemented by Red Ames, Jeff Tesreau, and Hook Wiltse. Yet, McGraw still found a role for a crafty spot-pitcher named Doc Crandall. In a run (1908-1913) that included three championships, Doc got to save a couple of dozen games making him the first de facto “closer” although nobody used that term, and certainly not in the presence of Matty or Rube.

A decade later, Fred (Firpo) Marberry further defined the role. Big, blazing and durable, Marberry alternated between starting and relieving duties in averaging over a decade more than 50 appearances a year for the ancient Washington Senators and excelling as they interrupted the Yankees’ Roaring Twenties reign of terror by copping consecutive pennants in 1924 and ’25. In 1926, Marberry had an unprecedented 22 saves in 64 appearances. As a true pathfinder, old Firpo belongs in the Hall of Fame.

Thus the role was secured. All subsequent champs had obligatory bullpen aces assigned to put out the fire. Waite Hoyt and Eddie Rommel did it for Connie Mack’s last dynasty in the Great Depression era. Succeeding Yankee titlists raised it to an artform with Wilcy Moore begetting Johnny Murphy who begat Joe Page who begat Johnny Sain who begat Ryne Duren, et al. On the Dodgers, there was first Hugh Casey, then Joe Black. On the Giants, Marv Grissom and Hoyt Wilhelm. On the Indians, Mossi and Narleski. On the Phillies, Jim Konstanty became the NL’s MVP in 1950 and in another year, Elroy Face won 18 games for the Pirates, all in relief.

Even crummy teams had superb firemen. When he was fully focused and cold sober, who was better than Ellie Kinder of the then wayward late 1940s Red Sox? For a too brief but truly spectacular three-year blitz no one was ever either better or more dramatic than Dick Radatz. Even with Dick Stuart, Eddie Bressoud, and Felix Mantilla behind him, the “Monster’ was sublime. The increasingly distinguished calling made another quantum leap in the ‘70s, thanks to Rollie Fingers, Sparky Lyle, Bruce Sutter, Goose Gossage, Soup Campbell, Dan Quisenberry, among others … many others.

At the start of the 1980s, Pat Corrales, crusty manager of the Phils, declared, “The Game’s becoming reliever-oriented.” Whereupon Ralph Houk, then the boss of the Red Sox, added: “I’d take a great reliever over a 20-game winner any time.”

To traditionalists, that was heresy. Stalwart “stoppers” who anchored rotations, never begged out, and pledged to finish what they started come hell or high water had always been the coin of the realm. Unquestionably it was nice to have a Dennis Eckersley lurking in the pen for insurance, but how could a true believer and certified throw-back like Major Houk prefer even gems like an Eck to genuine horses like Roberts, Spahn, or Feller, Gibson, Seaver, or Morris? How can a guy gifted at giving a couple of quality innings a week be more desirable than one guaranteed to give 330 innings over the length of a long, grueling season.

Then along came Mariano Rivera of the Yankees, who, with a comparably elegant bearing, became the Christy Mathewson of the relievers. For many, Rivera rather ended the argument.

In the new millennium, we’ve seen the role steadily expand to a degree of influence that would have seemed impossible only a decade ago and now, in 2012, we have another quantum leap, if you will, on our hands. Might one day a manager, armed with a computer printout of his opponent’s particular moods and circumstances, use his starter only the first inning then turn to his bullpen corps for the next eight, mixing and matching his way through the opponent’s lineup as if he were playing not baseball but chess? It would come as no surprise to this observer.

The extent to which relievers are being used this season is astounding. Five a game -- even in very low scoring games -- is becoming familiar, and using six is hardly unusual. I surveyed the full week of games beginning on Mother’s Day and scoured every box score I could find. Here are the results:

In 83 games, 496 relief pitchers were used. That’s an average of six per game (three each team) but in roughly half these games one of the teams used at least four relievers. Three times teams used seven relievers, one in extra innings. Just 12 starters pitched seven full innings, and only five of them (Verlander, Beachy, Lester, Lowe, and Morrow) pitched complete games.

In 1901, starters completed 86.4 percent of their games; in 1941, it was 46.2 percent; in 1981, it had dropped to 18.3 percent; and in this particular week in May of 2012 starting pitchers completed 6 percent of their games. I would not insist my randomly selected single week is a definitive sample, but I would bet it’s pretty darn close.

However, it’s not so much the decline of the complete game that’s arresting for that has long been a given. What’s more striking is the way relievers are being deployed. Teams like the Orioles, Rays, and Indians -- all interestingly doing better than expected so far this season -- are consistently trotting out four relievers a game. The Yanks, Sox, and Jays aren’t far behind, which is hardly surprising in the feverish AL East scramble where one-upmanship is the total obsession.

In one game in my survey period, the Royals used four pitchers throwing a total of 22 pitches in the 8th inning to hold the White Sox scoreless in a game KC won by eight runs. The Mariners did the very same thing against the Yankees also in the 8th: four pitchers throwing 27 pitches allowing one run -- in a game they’d win by four. Mix and match, I guess, although it may have been a computer making the calls with the manager merely following orders.

Bullpen by Committee is hardly new. The true inventor was not Tony LaRussa, who laid claim to the honor, but Dick Williams, maestro of those three-time Oakland champions of the early ‘70s. You may recall the A’s chorus line of Hamilton, Locker, Knowles, Pina, Lindblad, Fingers, and company. Since then, rare has been the manager able to resist the temptation. Some, like LaRussa, have done it well; others, like Joe Torre, not so well. But with a younger and healthier Rivera to bail him out, Torre nonetheless survived quite handsomely.

Where might it lead? What’s the limit? One consequence clearly is longer, slower, more convoluted, often aggravating games featuring oddly excessive strategizing. But a graver concern than mere issues of style is the health of bullpens. How many might yet blow up from egregious over-use this season? Are the Yankees telling us something? In case you haven’t noticed, relievers are dropping like flies all over the baseball map. And it is still early, old Sport.