When the Milwaukee Brewers traded for CC Sabathia on July 7, they were four games out of first place in the National League Central. Over their next 50 games, they ran up a .620 winning percentage, which would be good for 100 wins if carried through a full season, and lost half a game in the standings. Such is life for a team that plays in the same division as the Chicago Cubs.

Fortunately for the Brewers, first place doesn’t count for as much as it once did in baseball. Those same 50 games saw them rise from a half-game out in the wild card standings to a 4.5 games up, and Sabathia, who starts at home tonight against San Diego, is rightly getting enormous credit.

In 11 starts with Milwaukee, the defending American League Cy Young award winner and pending free agent has been invincible, with a 9-0 record, 1.43 ERA, and an 85/18 K/BB ratio in 88 innings. Absurdly, he’s even leading the NL in complete games with six, double the number of anyone in the league other than teammate Ben Sheets, and getting stronger as he goes: His last start, at Pittsburgh, would have been a no-hitter if not for a dodgy scoring decision. All of this has led to some understandable, if horribly misguided, chatter about him being a legitimate candidate for the Cy Young and MVP awards.

As unreal as Sabathia’s summer has been, though, runs like this aren’t as rare as you might think, something worth keeping in mind given that pending free agency. In this case the run is all the more dramatic for starting with a huge trade and a switch in leagues, and of course for all those complete games. (In today’s game, these carry a kind of moral significance, serving almost as demonstrations that only a lack of will keeps pitchers from tossing a full nine every other time they take the hill.) Some pitcher or other goes on a run like this more or less every year, and few have in subsequent years proved worthy of the kind of record-setting contract that Sabathia, 28, is all but assured of earning this fall.

In 2005, for instance, Andy Pettitte had an 11-game run in which he pitched 78 innings with a 1.50 ERA. Roger Clemens had his own tremendous 11-game stretch in 2005, running up a 0.95 ERA over 76 innings. (Write your own jokes about how exactly Houston teammates Clemens and Pettitte managed to do so well that year.) Pettitte has since been highly durable and only slightly above average; Clemens never pitched a full season again.

Other examples abound. Some don’t make a good comparison to Sabathia. In 2003, Kevin Brown had an 11-game run in which he pitched 78 innings with a 1.38 ERA and was out of baseball within two years, but he was also 38. Others, though, could be cautiously compared to Milwaukee’s big man. In 2002, at age 30, Pedro Martinez had a blinding stretch of 10 games in which he pitched 73.1 innings with a 0.86 ERA; that certainly wasn’t his last brilliant season, but you wouldn’t have done so well sinking $130 million into his right arm at that point. In 2003, 22-year-old Mark Prior finished the year out with 11 pennant drive starts in which he pitched 82.2 innings with a 1.52 ERA. He was never anything like the same pitcher again.

Probably the most hopeful comparison for Sabathia’s run from this decade, and in many ways the best, is that one that came when Johan Santana tore the American League apart for four months in 2004. Over 22 games (of which he completed only one), he struck out 204 men in 159.1 innings, and posted a 1.36 ERA. He was 25 that year, and had he signed a record contract that winter, his new team would have had a bargain.

That could well prove true of Sabathia, and it’s of course fair to note that he has little in common with most of the pitchers mentioned here. He’s older than Prior was, and throws fewer pitches a game. (Prior topped 124 pitches five times in his last six games in 2003, something Sabathia has done twice as a Brewer.) He’s younger than Brown, Pettitte, Clemens, or Randy Johnson, who had two distinct runs in 2001 alone that were similar to Sabathia’s hot stretch.

Still, as tremendous as he’s been, what teams thinking of signing him — and fans agitating for their teams to sign him — have to keep in mind is that almost by definition he’s at his absolute peak right now, and is thus certain to decline. It’s an obvious but essential point, and it would be a mistake to pay him in the future for what he’s doing for Milwaukee right now. Pitchers may not get any hotter than Sabathia is right now, but pitchers who do get this hot are no sure bets to ever do anything close again.

tmarchman@nysun.com