Sabermetric analysts will point out that a hitter having an unexpectedly good year may be benefitting from an abnormally high batting average on balls in play (BABIP), or that a pitcher's newfound success is mostly due to a high rate of stranding runners on base.
They'll argue that these values are largely dependent on luck, and are therefore unsustainable. As a result, the player's performance will decline going forward.
I'm not going to argue this. Studies show that on an infinite timeline, these stats are largely going to be near the mean values.
But the important thing to remember is that baseball is not played on an infinite timeline.
Think about a casino. The odds for all of the games are set up so that given a long enough period of time, the player will always lose.
And yet, there are plenty of instances of people winning at casinos. If they had continued to play for long enough, chances are that the odds would catch up to them and they would lose. But over the short term, they came out ahead.
Baseball is much the same way.
Sometimes, a player can get on a "hot" streak that is largely luck dependent. The stats may indicate that his success isn't sustainable and that he's probably going to suffer a drop off in the future. But that doesn't change what happened. All of the hits he got, all of the runs he scored, and all of the wins that the team earned as a result still count.
Therefore, it irks me to hear analysts downplay a player's accomplishments because they were due to luck.
For an example, look at former Phillies pitcher J.A. Happ.
On the surface, Happ had an oustanding year in 2009. He went 12-4 with a 2.93 ERA which was good enough to finish second in the rookie of the year voting for that season.
But apparently, his success was not due to any overwhelming skill he possessed, and it was more a result of good fortune.
Some analysts downplayed his acheivements. ESPN.com's Keith Law summed up Happ's season:
I said he's probably going to win the rookie of the year award, but not that he deserves to. Happ's 2009 season has been respectable, but his sub-3.00 ERA in no way reflects how well he's pitchedEven if his success was based on luck, does that diminish what he accomplished? In the end, does it matter if a pitcher was lucky or good? If he's helping his team win games due to luck, then I'll gladly take luck. If it wasn't for Happ's "luck" in 2009, the Phillies probably don't make it to the World Series.
In 2011, Happ did indeed have the drop off that many predicted. Ironically, peripheral stats showed that in contrast to 2009, he was actually unlucky in 2011. But that drop off can partially be attributed to being traded from the first place Phillies to the last place Astros. The quality of a the defense behind a pitcher will often affect his performance.
But even if 2009 was just a fluky year propelled by luck, it still happened, and we shouldn't discount it. Because luck or not, the end results still count.