Pettitte's raw numbers leave him grouped with any number of comparable pitchers who aren't going to be immortalized in the Hall of Fame. Per Baseball Reference, four of Pettitte's top five comps are pitchers who were teammates of his at one time or another: David Wells, Kevin Brown, Mike Mussina and Dwight Gooden. Gooden and Brown have already been rejected by the Hall, Wells has no case and Mussina has a good chance of following Bert Blyleven and Tim Raines as the stathead favorite who gets limited love from the voters and spends a long time on the ballot. Four Hall of Famers, led by Juan Marichal, show up on Pettitte's 10-deep comp list, but two of those -- Catfish Hunter and Herb Pennock -- are among the weaker of Cooperstown's elite.
Pettitte's raw statistics fall short of the standard for the Hall of Fame, but not by enough to keep him out of the discussion. Pettitte, by dint of the timing of his career, is going to be the focal point for two arguments about the electorate's standards: that the line for starting pitchers has gotten too high, and that postseason work should be given greater weight then it ever has.
The Hall voted in Bert Blyleven a few weeks ago, a pitcher who was made to wait for 14 years despite being wildly overqualified for the honor. Blyleven raised the level of starting pitching in the Hall, and that it took nearly his entire period of eligibility for him to get in is the leading indicator that the BBWAA is asking too much. Blyleven was the first starting pitcher elected since '99 (Nolan Ryan), and the first to be elected without having 300 wins since '91. Hall voters in the '50s were putting in Ted Lyons (260-230, 3.67 ERA in 4,161 IP), Dazzy Vance (197-140, 3.24 ERA in 2,966 IP) and Dizzy Dean (150-83, 3.02 ERA in 1,967 IP; basically six good seasons). In the '70s they elected Robin Roberts (286-245, 3.41, 4,688 IP) and Bob Lemon (207-128, 3.23, 2,850 IP). In the '80s, they put in the heroes of the low-offense era by the truckload: eight starters in 12 years, including Hunter (224-166, 3.26 ERA in 3,449 IP) and Jenkins (284-226, 3.34 ERA in 4,500 IP).
That stopped in the '90s. Blyleven was better than most of the pitchers in the above group, but had to wait 14 years. Kevin Brown was better than many of them, and he's already off the ballot. The voting pool, having shoveled in a whole bunch of starters with fewer than 300 wins and fairly common ERAs and IP totals, put away the shovel around about '91 and decided that future starters wouldn't be measured against the established standard, but against the top of the pool. They have not done this for any other category of player: Jim Rice is in, Andre Dawson is in, a bunch of relievers are in. For starting pitchers, though, you now have to win 300 games or have Pedro Martinez's track record to be considered, and that's ignorant of history.
The problem with this is twofold: one, pitchers who played in the '90s are going to have higher ERAs than those elected by the writers, particularly the ones many consider the Hall standard: the sub-3.00-ERA, 275-plus win pitchers of the '60s and '70s. Second, usage patterns have changed to keep starters from racking up the starts pitchers from that era did, limiting their innings and wins totals. There's a perfectly good reason for this: pitching became harder, and it was impossible to sustain a long career while being asked to make 40 starts and throw 300 innings per season. The usage patterns of the '60s and '70s worked when four hitters in every lineup slugged .320. When that changed, when pitchers had to work harder to every hitter, they were able to provide less quantity. The voters are holding Brown, and the pitchers to follow in his stead, to a standard that ignores the changes in the game. Pettitte, judged in the context of his time, is as qualified as many of the pitchers elected by the BBWAA in the past. He's not an inner-circle Hall of Famer like Roger Clemens or Greg Maddux; he's just a great one who fits in with Hunter, Lemon, Dean, et al.
That's not Pettitte's strongest argument, however. Pettitte's case is bolstered by the season's worth of work that doesn't show up in his WAR or WARP or his JAWS profile. Pettitte threw 263 postseason innings, with an ERA of 3.83, in pitching for eight pennant-winning teams and five world champions. Pettitte's first season, '95, was also the first year of the expanded postseason, and in playing for the Yankees, he had ample opportunity to rack up postseason starts. While some feel postseason work should not be considered part of a Hall case because not every player has the opportunity to participate, the correct approach is to consider it on a case-by-case basis, not holding the absence of it against players such as Ernie Banks or Ron Santo, but giving due credit to those players who performed well in the highest-leverage games of all. Winning a championship is the goal, of course, not racking up wins or innings or WAR, and playing well in the playoffs and World Series has considerable value toward that goal.
The argument becomes even more essential for modern players, who are increasingly judged by their postseason performance. Think about the way Barry Bonds and Alex Rodriguez were criticized for stretches of postseason failure, small samples of playing time that served to create an indelible stain on each player's career. Conversely, players such as Derek Jeter and John Smoltz, with strong playoff credentials, have reputations to match. Teams are judged this way as well, as successful franchises with division titles and long runs of success, such as the Indians and Braves, aren't as well-regarded because of a perceived (or in the Indians' case, actual) shortfall of championships. MLB itself has put greater weight on the postseason in its structure and marketing. It's only fair to consider that performance similarly in evaluating players for the Hall.
Pettitte's postseason body of work pushes him over the top, as much on quantity as quality. His postseason ERA is just slightly better than his career mark, which is a positive; postseason competition is quite a bit tougher than regular-season competition. Pettitte made a whopping 42 postseason starts, with his team going 26-16 in those games. He pitched into the seventh inning 30 times, making 25 quality starts. He had some huge games in there: 8 1/3 shutout innings in Game 5 of the 1996 World Series; 7 1/3 shutout innings in the clincher in '98; 8 2/3 innings with one run allowed in Game 2 of the '03 Series. Pettitte was never the Yankees' (or Astros') ace, but he was almost always the No. 2 man, and over his career, a highly-valued contributor when the calendar turned to October.
On traditional metrics, Pettitte may not look like much. His career is relatively short for a Hall of Famer, he didn't rack up lots of awards or award votes and his statistics are not overwhelming. However, accounting for the usage patterns and offensive levels of his day, as well as the increased importance of the postseason relative to the regular season -- and his work in those games -- the case for Pettitte becomes clear: he is a Hall of Famer.