By the Numbers: Names to acquire and sell high

We have nestled into that wedge of the season between the All-Star break and the major league trading deadline, meaning that trade season has also come to Fantasy.

Just as with draft season, scarcity rules the day. It takes a bit of scrolling down the Most Traded list to find a single catcher, second baseman, or reliever, and Jimmy Rollins and the disabled Jose B. Reyes are the only shortstops among the 35 most-swapped players. Owners looking to shore up their roster at these positions have to be prepared to pay a premium or be willing to roll the dice with free agents.

Nearly everyone at or near the top of the Most Traded list plays a position where there are plenty of players with quality stats. Not surprisingly, many of the most traded players are also underachievers. Buyers are attracted to these players because they are looking for a bargain; owners are willing to deal because, in all likelihood, they have lost patience.

The corollary to this trend is that players who have overachieved this season have seldom been dealt over the last two weeks. It is easy to get emotionally attached to the players whom you draft, especially the late-round fliers who turn out to be team MVPs. In some cases, the reluctance to part with these unlikely finds can serve an owner well. Wandy Rodriguez and Adam Lind, for example, were underappreciated on Draft Day, but both have been among the most productive Fantasy players this season. An owner's decision to hang on to either of these "secret weapons" would be a sensible one, because their performances fit a pattern of sustainable skill growth that bodes well for a successful second half. Not every surprise performance is the result of overachieving. However, in cases where a player has genuinely overachieved, owners would be best served to enjoy the gift and then start working the phones or e-mail.

Which underachievers are due for better second halves, which buyers can exploit? And which overachievers should teams be looking to sell? Here are some names for both buyers and sellers to consider.

Buyers beware: not every slumping star is a bargain.

Each of the six most traded players are stars who have not performed up to their projections to date. Some are worth pursuing, while others are best left for other owners to acquire. Here are those six trade targets, in order of the frequency they have been traded.

Alfonso Soriano, OF, Chicago Cubs: He has been traded more than any player in Fantasy over the last two weeks, and that means there are lots of buyers who may be sorely disappointed. Since May 1, Soriano has hit just .217 with eight home runs. An unusually high ground ball rate is behind his sagging average and power. Everything seemed to be fine back in April, so you have to wonder if there is something wrong with him besides his jammed finger.

Johan Santana, SP, New York Mets: He has had better results lately, but Santana hasn't struck out more than five batters in a start since May 27. This stretch of nine starts with this few strikeouts is the longest in his career by far. This extended downturn should be a source of concern and raise doubts as to whether you would get enough value from Santana, given what you would probably have to pay.

David Wright, 3B, New York Mets: Even an unearthly .430 batting average on balls in play (BABIP) can't disguise Wright's down season. His normally consistent whiff rate is far above his norm, and he has all of five home runs heading into late July. His homer rate should pick up -- he has hit 25 doubles and is still hitting flyballs -- but his batting average has nowhere to go but down. It's not a good idea to be on the buying side of a trade for Wright, unless you can really get him at a discount.

Matt Holliday, OF, Oakland: You can't blame it all on Oakland Coliseum. An 18 percent line drive rate speaks to his dwindling power, and so does his shockingly low .127 Isolated Power in away games (as compared to .177 at home). Even a trade might not rescue his season.

Cole Hamels, SP, Philadelphia: As I've written recently, there is nothing wrong with Hamels that much better luck with BABIP won't solve. And to the reader who suggested that Hamels' down year is due to the defensive shortcomings of Raul Ibanez, note that the Phils' left fielder is gazelle-like compared to his predecessor, Pat Burrell. Ultimate Zone Rating, courtesy of the good folks at Baseball Info Solutions, says so. But I digress. Hamels is someone to target if you're ready to make a big pitching move.

CC Sabathia, SP, New York Yankees: Sabathia's season has been moving in the opposite direction of Santana's. After posting a low strikeout rate in April, Sabathia has been more like his regular self since then. Though he hasn't slumped as severely as Hamels, you may still be able to get Sabathia at something of a discount.

Sellers, here are your best opportunities to cash in. There are plenty of overachievers who are not getting many changes of scenery in Fantasy. Here is my top 10 list of sell-high candidates (not in any ranked order), none of whom are anywhere close to the being among the 100 most traded players.

Jason Varitek, C, Boston: He has experienced a power hitting renaissance this year, but his home run and doubles rates, and even his whiff rate, have been too good to be true. Help him find another owner before the home run train leaves the station for good.

Alberto Callaspo, 2B, Kansas City: The doubles binge has come to an end. Callaspo has collected only six two-baggers in his last 95 at-bats. This is not bad production, but owners may still be willing to pay for the 50-plus doubles pace he set earlier in the season. Already, he is reverting back to being a two-category player, helping with batting average and runs but nothing else.

Pedro Feliz, 3B, Philadelphia: The .255 career hitter managed to sustain a high batting average and BABIP through mid-June, but both have tumbled since. Since his high water mark of a .318 batting average on June 14, Feliz' line drive rate has slid from 25 percent to 21 percent, meaning many fewer base hits on balls in play.

Asdrubal Cabrera, SS, Cleveland: Like Feliz, Cabrera benefited from an early season line drive spree. His BABIP, once over .400, is now down to .363. There is still some downward adjustment to come.

Jason Kubel, OF, Minnesota: He is coming off of a very good June that was a little too good. Some of this season's power gains are for real, but more flyballs should be adding up to a lower batting average, not one that is 40 points higher than last year's.

Franklin Gutierrez, OF, Seattle: His heightened batting average can be attributed to a newfound aversion to flyballs, but then how do you explain a home run rate that has doubled since last year? Maybe Gutierrez is hitting the ball with much more power this year, lifting both his batting average and home run total. More likely, the sudden and drastic change in his profile suggests that something, or possibly both things, will have to give.

Doug Davis, SP, Arizona: Less than two weeks ago, I wrote that Davis was the epitome of a sell-high candidate. He still is. His skill ratios do not suggest that he should be having the career year he appears to be having.

Brad Bergesen, SP, Baltimore: I like pitchers like Bergesen whose strengths are low walk and flyball rates, because they are often the most valuable pitchers among those who fly under the radar of many owners. Now that he's owned in a majority of the leagues on this site, we can't really say that he's under anyone's radar. Bergesen has actually become a bit overrated, and he has been getting help from a healthy dose of run support and a low BABIP.

Randy Wells, SP, Chicago Cubs: Not to say that Wells isn't an effective pitcher, but I'm not buying the ultra-low walk rate, sub-1.0 HR/9 rate, and the 3.00 ERA and 1.15 WHIP that they have produced. Deal him to someone who does and is willing to pay for it.

David Aardsma, RP, Seattle: I have been hating on Aardsma throughout the season. Actually, I don't hate the player, just his numbers. This is just the latest cue to mind the many signs of an impending second half downturn, which include a fluky HR/9 rate, a low BABIP and a high strand rate.

Al Melchior was recently a Fantasy columnist and data analyst for Baseball HQ and will be providing advice columns for CBSSports.com. Click here to send him a question. Please put "Melchior" in the subject field.