Looking at a hitter's advanced statistics can help make sense of a player's early-season performance. Let's break down a few of the more telling stats, so owners can get a better read on their fantasy squad. These stats can be found on fangraphs.com, one of the best baseball stat sites around.
BABIP (Batting average on balls put in play): How many of your player's batted balls avoid fielder's gloves? Or how many balls put in play end up being hits? If a player's BABIP is very high compared to the league's average of about .300, owners can deduce that the player's batted balls have been relatively lucky. On the other end of that spectrum, if a hitter has an uncharacteristically low BABIP, he's making contact but hitting the ball right at fielders. A player's speed also comes in to play here, as a fast player will be able to beat out more infield hits than a slower player. Also, a player that faces a lot of shifts will have a lower BABIP in general.
BB% (Walk percentage): If a hitter has a high walk rate, that means he's reaching base a lot, even though he's not necessarily improving his batting average or adding to his counting stats. The league's average walk rate for non-pitchers in 2013 was 8.1 percent.
K% (Strikeout percentage): If players are striking out, they're not only missing an opportunity to get on base and improve their batting average and counting stats, but they're also killing their chances of moving runners over or knocking them in. The average strikeout rates for non-pitchers was 19.3 percent last season.
ISO (Isolated power): This deciphers a player's raw hitting power by measuring how well they have been able to hit for extra bases. (The easiest way to calculate this is by subtracting a player's batting average from his slugging percentage.) In other words, the weighted percentage of extra base hits they get per at bat. Small sample sizes, like five weeks' worth, don't really project out like you would hope. So look at this number among other numbers before making any rash decisions. The average ISO for a major-league hitter is about .145 to .150.
Don't just look at these player's stats compared to all of the other players in the league or even at their position. You want to look at their stats compared to what they've usually done season over season. If strikeout rates are much higher or lower than normal, try to figure out why. He could have made some offseason changes that have not made a positive impact on his swing yet, or he may have a lingering injury that's affecting his swing.
If you can figure out some of the puzzle, you are in much better shape than you were looking at your players at face value. And that will make a big difference in how you valuate them going forward.
Hitters of the week
Troy Tulowitzki, SS, Colorado Rockies -- Stats this week: .619 BA, 2 HR, 8 RBI, 9 runs scored
Once again, Tulo is destroying opposing pitchers, leading the majors with a .400 batting average, and his fantasy owners can't hold their breath anymore. The powerful shortstop would be a top-three draft pick every season if he stayed healthy, but he averaged just 105 games played over the past three seasons, and he has played more than 130 games just twice in the past six seasons. Injuries that knock him out of the game are just part of the problem, as he also has injuries that he tries to play through, which hurts fantasy owners nearly as much. His career slash lines in the month of April before this season were .152/.226/.238. This April? He posted .364/.477/.727 slash line last month, which happened to be the slugger's best month in his career. You can't predict injuries, but fantasy owners are hoping he's taking his vitamins.
Desmond Jennings, OF, Tampa Bay Rays -- .355 BA, 3 HR, 3 RBI, 8 runs, 3 SB
After hitting a home run in three consecutive games, Jennings is on pace for career numbers across the board, which would make him a 20-30 player for the first time. He's striking out about as much as usual (approximately once every five plate appearances), and while his BABIP is high (.354), it's not enough to expect a huge drop. A 20-30 season would make him a first-round pick in 2015 fantasy leagues, but we can reasonably expect he's going to tail off at some point. His age-27 breakout season continues, and manager Joe Maddon told MLB.com he's not really surprised. "Every at-bat, he's into it, accepting his walks, not expanding his strike zone and just keeps getting better. It's a real treat watching him. This is kind of what we thought he could look like."
Anthony Rizzo, 1B, Chicago Cubs -- .357 BA, 3 HR, 6 RBI, 6 runs, 1 SB
Another guy that hit a home run in three consecutive games this past week, Rizzo is putting together a very impressive start to his season. He's walking more, striking out less and hitting with more power. All of that put together can create a strong fantasy season.
Hitters of the weak
Hanley Ramirez, SS, Los Angeles Dodgers -- Stats this week: .172 BA, 0 HR, 3 RBI, 0 runs scored, 0 steals
Ramirez has struggled with injuries this year; he missed a couple games in late April with a bruised thumb, and a sore hand affected him in the middle of April. The 30-year-old middle infielder has just three home runs and three stolen bases on the season, which is hurting a lot of fantasy owners that took a chance on him in the first round. At worst, owners expected great stats in limited action because of injuries, but not 31 games played and subpar stats.
Ben Zobrist, 2B/SS/OF, Tampa Bay Rays -- .111 BA, 0 HR, 0 RBI, 2 runs, 1 SB
The big boys in the AL East just have Zorilla's number, as you can see in his past week at Fenway Park and Yankee Stadium. Last season, in 37 games against the Red Sox and Yankees, he had just one home run and a .234 average in 37 games against those two teams. With eligibility at second base, shortstop and outfield, Zobrist should be compared to other middle infielders more than outfielders. For the season, he's still a top-five shortstop, but as an outfielder, he's barely in the top 20.
Freddie Freeman, 1B, Atlanta Braves -- .087 BA, 0 HR, 1 RBI, 0 runs, 0 SB
Freeman's incredible start to the season spoiled us, as he had 14 RBI in his first 18 games of the season. Possibly not coincidentally, his progress slowed in late April, when he had a broken piece of contact lens removed from one of his eyes. Since then, he's hitting just .146 with one home run and four RBI. Figure he'll snap out of that funk soon.
Buy, sell or hold
Buy: Matt Adams, 1B, St. Louis Cardinals
We spoke about shifts earlier, and how you have to take that into account with some players' BABIP numbers, since they're facing specialized defenses set up for their swings. Adams is a barrel-chested, left-handed pull hitter that had success in 2013 as a rookie, hitting 17 home runs in 108 games. FanGraphs' Jeff Zimmerman points out that his batting average dropped nearly 60 points when teams decided to employ the shift against him last season. His power remained, but his average declined. This offseason, he worked to start going the opposite way to beat the shift, and his batting average (.339) and BABIP (.413) show that he's successful at it. Unfortunately, his power -- the reason you drafted him -- has dipped considerably (.220 ISO last season compared to .153 this season), and he has just two home runs. Once he figures out to spread the ball around and hit for power, which is possible considering the changes he has already made, he'll be a run-producing powerhouse again.
Sell: Norichia Aoki, OF, Kansas City Rams
I grossly over-estimated what the Royals offense would be able to do with Aoki hitting atop the lineup. The team is ranked 25th in the major sin runs scored, which is even worse than they did last season. While I want to blame the 32-year-old leadoff hitter, we can also cast blame on the rest of the team. The Royals have just 12 home runs on the season, which is worst in the majors, and Aoki is striking out way too much (14.5 percent) in his first season in the American League. That should improve as the season ages, but he'll need help before fantasy owners can be happy about owning him. With a .279 batting average, you should be able to move him in a trade.
Hold: Yoenis Cespedes, OF, Oakland A's
While we talk about small sample sizes above, it's important to also consider changes in approach. Cespedes, through the first five weeks, has an improved contact rate, with a K-rate down more than five percent. He's swinging at bad pitches less, and he's reaching base more, with a walk rate that has nearly doubled from last season (12.2 percent compared to 6.4). A shortened swing has helped him in the early going, and now he's close to a 100-RBI pace, which would be the first time in his career he reached that mark.
Rookie hitter spotlight
Nick Castellanos, 3B/OF, Detroit Tigers
When the Tigers traded slugger Prince Fielder to the Rangers for Ian Kinsler, the onus was immediately put on the rookie to step in at third base, as Miguel Cabrera moved over to first base. The team needed him to replace at least some of Fielder's power in the lineup, and he started the season strong, hitting .274 with three home runs and 13 RBI in his first 17 games. But over the past week, he went 2-for-20 (.100) with one solo homer. Fortunately, he's coming up against a very weak pitching schedule this week, as are all of the Tigers, as he faces the Astros and Twins at Comerica Park. Those two teams are among the worst in team ERA.
By the numbers
420 -- Feet that Giancarlo Stanton has hit seven of his 10 home runs this season. He leads the majors in home runs hit in that distance, and one can only imagine how he'd be doing in a hitter's park.
99 -- Bases Dodgers 2B/SS Dee Gordon is on pace to steal this season. That would be the most steals since Rickey Henderson stole 93 bags in 1988.
65 -- Number of home runs the Royals are on pace to hit this season, which would be the lowest HR total since the Cardinals hit 58 home runs in 1986. That includes the strike-shortened 1994 season.
12 -- Stolen base attempts made by the Marlins through the first five weeks of the season, which is a majors low. They ranked 18th in the majors in SB attempts last season with 107, but they're only on pace for just 62 attempts.
5 -- Games the Reds have scheduled this week, which could hurt your Head-to-Head teams if you play some of their borderline fantasy hitters.
3 -- Home runs hit by Ben Zobrist in 82 games against the Red Sox and Yankees since 2012.
.500 -- Tulowitzki's on-base percentage this season, which happens to lead the majors. That means he's getting on base once out of every two at-bats so far this year.
.487 -- BABIP for Matt Adams when teams employ a shift this season.
David Gonos is a fantasy sports veteran of over 20 years and over 100 fantasy leagues. You can also follow him @davidgonos on Twitter.