If you don't know what exactly you're looking at, sabermetrics can be confusing or intimidating.
Here are a few sabermetrics you need to know with (hopefully) simple explanations.
WAR If you have watched "Baseball Tonight," there's a great chance you've heard the term WAR.
It stands for Wins Above Replacement, and it's a tool that sums up in one number exactly how valuable a player is to his team.
We first must understand "replacement level" and what exactly that is.
A replacement level player is generally regarded as a player that could be called up from triple-A and be placed in the lineup immediately.
There are a few benchmarks that can tell where a player stands based on his WAR.
The following is for position players, as starting and relief pitchers have a different standard for WAR.

• Starter: 2+
• Good player: 3-4
• All-Star: 4+
• MVP: 6+

WAR has been the focus of the Mike Trout-Miguel Cabrera American League MVP debate for the last two years.
Trout has posted a WAR of 10 or better both seasons, which is tremendous.
Cabrera hasn't been a slouch either, and has posted WARs of 6.
8 and 7.
6 in 2012 and '13, respectively.
True, Cabrera's WAR in both of those years was very impressive, and likely worth winning the MVP.
Trout, however, was better, and sabermetricians will by and large vote for him every time.
WAR isn't perfect, but it's a valuable tool.
If you are learning sabermetrics, it's a good tool to start with.
Players can have a WAR below 0.
For instance, if Atlanta Braves fans are wondering how poor BJ Upton played last season, the answer is -0.
6 WAR.
In theory, the Braves could have brought a player up from triple-A and been better off.
Isolated Power (ISO) Put simply: Isolated power = slugging percentage - batting average What ISO effectively does is take the singles out of slugging percentage.
Slugging percentage is the stat that many people will mention in reference to how much power a player has.
Here's a small issue with slugging, and, really, what makes ISO a better indicator of power.
The following are stats for Chris Johnson of Atlanta and Prince Fielder of Detroit (last year, as he now plays for Texas) from last season.

• CJ: 34 doubles, 12 home runs, .
  321 AVG, .
  457 slugging, .
  136 ISO
• PF: 36 doubles, 25 home runs, .
  279 AVG, .
  457 slugging, .
  178 ISO

As you can see, Fielder is the better power hitter, but you wouldn't know it by just looking at slugging percentage.
That 42-point difference in ISO is seen in their batting averages.
Based on ISO, we can tell that Fielder has above average power, while Johnson is just less than average.
Fielding Independent Pitching (FIP) FIP is basically what a pitcher's ERA "should have" been over a given period of time.
Essentially, pitchers can't control what happens once a ball is actually hit, and that's what FIP accounts for.
FIP looks at what a pitcher can control: strikeouts, walks, home runs, and hit by pitches.
FIP is a good predictor of what a pitcher may do in the future.
It's on the same scale as ERA, so under 3.
00 is very good, 4.
00 is average and 5.
00 isn't so good.
So if a pitcher's ERA is 4.
50 and his FIP is 3.
80, you can see he's been a little unlucky, and his ERA should come back down soon.
Likewise, if his ERA is 3.
80 and his FIP is 4.
50, don't expect that good performance to keep up for too long.