Today, I am going for a dual thread. First, I am going to do a quick look at the few stats I examine when I am looking at a player. I will used the stats freely available at FanGraphs. They can be all added to an easy to read personal dash board at FanGraphs. Also, feel free in the comments to ask any stat/sabermetric questions (try to limit the Wins and RBI jokes).
Stats for Hitters (for a definition of each stat go to this link)
Age - Reference to know if a player's skills should be increasing or decreasing. Peak age for speed is around 22-years-old and hitting is at age 27.
Games and plate appearances - Context needs to be added to the other stats. A player hitting a .350 AVG in 60 PA is less impressive than a hitter hitting at that level in 600 PA.
HR and HR/FB - Chicks dig the long ball. They help to determine the player's power.
SB and CS - Does the player attempt stolen bases (thinks he is fast) and his success rate (is he fast and smart).
K% and BB% - Determines the player's plate discipline.
wOBA - Gives the total value of a hitter's production adjusted to the league average OBA. Each different event (walk, out, home run, etc) is given its own weighting depending on the number of runs it generates on average.
AVG/OBP/SLG/ISO - By using these four stats, the type of hitter can be found in more detail than by just using wOBA. A .200/.350/.450 would be more walk and power prone than one who hit .300/.400/.400 even though they would have similar wOBA.
BABIP - Helps to show how many of his batted balls are dropping into play. Is his BABIP, which takes a long time to stabilize, the same as in the past (talent) or is it high or low compared to his norm (luck)?
wRC+ - A contextual stat where a value of 100 puts the player's hitting at league average. A value of 120 would mean they are 20% better than the league average. A value of 80 would mean they are 20% worse than the league average.
UZR - The number of fielding runs, above or below the league average, for a player prevents or gives up. Not a panacea for measuring defense. I usually half the value (positive or negative) to give me an idea of the player's defensive value.
WAR - Total value of a player including position, hitting, fielding and base running adjusted to Wins over a replacement player.
Age - Gives a reference for a pitcher. All stats will on average decline as a pitcher ages except BB% which bottoms out around age 28.
Games, Games started, IP - Gives a background context for the rest of the stats. A pitcher's fastball speed may have decreased, but by looking at these three, it may have been because he moved from the bullpen to the starting rotation and now needs to pace himself over the course of a game.
K/9, K%, BB/9, BB% - I useall four right now, but just one of the K and BB values could be used. I learned what was a good or bad value with the X/9 values in the past. The % values are a better representation of a player's talent though.
SwgStr% - Early indicator a pitchers ability to miss bats. I quick rule of thumb I use is SwgStr% + 9% = K%.
HR/9 - Is the pitcher prone to home runs? It should always be under 1.0.
GB% - Helps to show if the pitcher can keep the ball on the ground. 50% is good.
ERA/FIP/xFIP/SIERA - These 4 help to explain how a pitcher is preventing runs from being scored. ERA is the earned runs allowed. FIP used BB, K and HR to estimate a player's ERA. xFIP uses the same BB and K values, but uses the league average number of home runs per fly ball to estimate the number of home runs. SIERA used several more factors (GB%, velocity) and attempts to give a still more accurate estimation of ERA. Look for differences to see if a pitchers runs allowed will change.
BABIP and LOB% - They show how many balls in play get through the defense and with the hits, how many runners get home. A .290 BABIP is around league average now along with a 70% LOB%. These two, along with HR/9, help to explain the differences in ERA/FIP/xFIP/SIERA. A FIP higher than the other 3 could be sign the pitcher has allowed a higher percentage of home runs (wind was blowing out one day). The key is to see if a difference exists and why.
FBv and Zone% (pfx) - I use these two to look to see if a pitcher is throwing the same from year to year. Velocity is pretty simple, if they can keep it, they will remain the same pitcher. Zone% looks to see if a pitcher throws pitches in the strike zone. If the value drops below 47%, the pitcher may be struggling with pitches and be injured.
RA9-Wins and WAR - RA9 Wins is the number of wins the player produces due to their ability to prevent runs. WAR is FIP based and gives a player value based on their ability to control factors under their control, K, BB and HRs
By using the above stats, a good picture of a player's talent/results can be created. Thoughts on the list.
Also, remember to ask any other stat related questions. I won't bite.