Despite offensive levels being up around the majors, there are many sluggers that aren’t pulling their weight. With nearly one-third of the season already wrapped up, it’s time to start making decisions about which hitters are likely to bounce back, and which ones are likely to continue to disappoint. Below we have a hand-picked list of some of the hitters with the lowest Isolated Power (ISO) figures in the league; all of these players were expected to hit for some power, but so far, none of them have delivered.

Hitter             AB  2B  3B  HR   ISO
Carlos Guillen     90   4   0   0  .044
Russell Martin    121   6   0   0  .050
Alexei Ramirez    110   3   0   1  .055
Bobby Abreu       130   6   1   0  .062
Pat Burrell       108   4   0   1  .065
Geovany Soto       89   3   0   1  .068
Conor Jackson      99   4   0   1  .071
Mike Aviles       108   3   1   1  .075
Magglio Ordonez   129   4   0   2  .077
Brian Giles       139   5   0   2  .079
Ryan Church       113   6   0   1  .080
Kevin Kouzmanoff  135   6   1   1  .082
Jhonny Peralta    132   8   0   1  .083
Ty Wigginton      117   4   0   2  .085
James Loney       142   7   0   2  .091
David Ortiz       130  10   1   0  .092
Dustin Pedroia    142  11   0   1  .098
Edgar Renteria    121   6   0   2  .099
Jimmy Rollins     148   7   1   2  .102
Nick Johnson      132   5   0   3  .106

Alexei Ramirez was supposed to be a great option for fantasy purposes this year, with eligibility at shortstop and second base in addition to his power output. Things have not worked out as planned though, and Ramirez is hitting just .218/.254/.273 to begin the year. You may think this is because of his tendency to swing at everything that comes close to the plate-as well as plenty of pitches that do not-but he has improved in those areas during the first two months of the season. Last year he walked in 3.6 percent of his plate appearances, but he’s bumped that up to 5.2 in 2009. He’s seeing 3.7 pitches per plate appearance, a significant improvement over 2008’s 3.3 mark. He’s also not swinging at as many pitches outside of the strike zone (down to 36.8 percent after 42.7 last year), so we can see that his patience has improved overall. The poor performance looks to be a combination of bad luck and poor timing, as his BABIP is just .242, while he’s popping up on 30 percent of his fly balls, which suggests a timing issue. If Ramirez works on his swing to bring it back to form while adding this year’s more patient approach to things, he should be able to contribute power to both your fantasy team and the White Sox as the year goes on.

Unlike Ramirez, Bobby Abreu isn’t having any trouble avoiding the gloves of the defense; he’s hitting .300, and walking in nearly 13 percent of his plate appearances while keeping his strikeouts to a minimum. Abreu’s problem is more that his power has disappeared completely; he posted an ISO of .176 in 2008 with the Yankees, but looks more like David Eckstein out there for the Halos in 2009. Part of the problem is that Abreu is hitting the ball on the ground far too often, and it’s hurting his power: his ratio of ground balls to flies of 1.9 is far and away his loftiest since 2003, when he hit 1.8 with the Phillies, and those grounders have come at the expense of his line drives. Abreu does not hit titanic home runs, and he doesn’t hit that many fly balls either; he gets many of his extra-base hits and homers on well-struck liners, and he normally hits an above-average number of those. Abreu’s liner rate since 2002 is 23.1 percent, but he’s down at 18.4 this year. While this has been great for his infield hits total, you drafted him to pick up 15-20 homers. I’m not sure he will be able to return to that form this year though, as pitchers are attacking him early in the count-he’s seeing first-pitch strikes nearly 63 percent of the time, which is well above both the league average and the rates he normally sees. He’s also popping up quite a bit, which leads me to believe he’s not catching up to pitches on the inside part of the plate as often; he’s rarely pulling the ball, which gives credence to that idea, especially since most of his homers were to right field in 2008. Abreu is still a good player to have around, but expecting him to hit for power at this stage may be asking too much.

Pat Burrell has just one homer after nearly two months, which is not what the Rays had in mind when they signed him. It’s not just his power that is down though, as he’s also walking less often, and still managing to hit for a poor average. This has effectively killed his fantasy value, especially since he doesn’t add anything on a speed or positional value. Burrell has been playing with a stiff neck and been forced to sit out because of it a few times, which could have something to do with the lack of power. There are some signs that show this could be something else though: Burrell hit just .215/.313/.413 after the All-Star break in 2008, and that dip in power has become more problematic in 2009. Pitchers know he is having trouble, and are coming at him in the strike zone more often and earlier in the count, which gives Burrell fewer chances to hit a good pitch in a hitter’s count. According to Inside Edge, he’s hitting just .178 against curveballs, and pitchers are throwing them more often then they have in years past. Apparently, the American League doesn’t just have the better pitchers, it has the smarter ones too. Except for the fact that it’s hard to believe Burrell could hit this poorly all year, there’s no compelling evidence to say he won’t continue to struggle. Rays fans are already taking note and assuming the worst, so it may be time to jump ship while you can.

Back in Philadelphia Burrell’s former teammate, Jimmy Rollins, is also struggling, hitting just .216/.264/.318 to begin the year. Rollins’ walk rate, which he boosted last year, is back down, and is the lowest it has been since 2000 when he first came up. He’s hitting more fly balls again, but not solidly, as his lack of power production shows, and in addition his liner rates-usually well above-average and the key to his success as a hitter-are now just under 18 percent. Like many of the other players on this list, Rollins is popping up frequently, to the point where it’s clear there is something wrong with his swing, his timing, or both. Pitchers aren’t treating him much differently than in the past, and he’s taking the same number of pitches that he usually does, but his results are markedly different. This situation, like Alexei Ramirez, is most likely something that can be cleared up with tweaks to his approach and swing. If Rollins can cut down on the number of popups he’s producing by leveling out his swing or improving his timing, he should be able to send the ball flying like he normally does, rather than hitting it straight up for an easy out. He’s a good buy-low candidate if his current owner is impatient or nervous.

The James Loney we saw back in 2006 seems like a distant memory these days. The current version is hitting .275/.350/.366, continuing his trend of declining ISO numbers-.275 to .206 to .145 to this season’s middle infielder-like .092. What’s strange about this is that Loney has improved his approach, adding more walks (up to 10.7 percent of his plate appearances) while also cutting down on strikeouts (now under 10 percent, at 8.5). He’s cut down on the number of pitches he swings at outside of the strike zone, and has also increased his overall contact rate. So what’s the problem, given that all of these core pieces of his approach seem to work well? Loney is a victim of bad luck, for the most part; he’s hit liners at an extreme rate of 25 percent, yet managed a BABIP of just .289. Loney has been hitting everything into the gloves of the defense, and though that doesn’t necessarily account for the missing homers, it certainly tells us where plenty of singles and doubles have gone. Given more time, his liner rate should even out, with many of those outs turning into the hits they ought to be.

A version of this story originally appeared on ESPN Insider Insider.