As the fantasy season wears on, owners are now aware of the problems that their squads face; unless they just drafted very poorly, most owners will realize that they’re lacking in one or two categories that are causing problems week after week.

While the problems may be obvious, the solutions are usually frustrating; most of the players remaining on the waiver wire won’t help much, and other owners may either be irrational or tentative to trade ideas (or even worse, inactive).

Viewing some recent trades that have been accepted in Yahoo! leagues help illustrate current trading trends:

Grady Sizemore/Roy Halladay for Chien-Ming Wang/David Ortiz

This was a conventional trade of both expectations and needs. Ortiz is a notoriously slow starter who has once again failed to hit the ground running this year. Sizemore has been fine but not his usual outstanding self. Halladay (3-5) continues to take hard-luck losses for Toronto, while the Yankees have given Wang enough support for him to be 6-1 despite Halladay having the more impressive stats. The pitchers are most likely a tit-for-tat thrown in by the original Sizemore owner to convince the second owner to part with Ortiz, who at this point would need to explode in June and July to reach his numbers from years past. They don’t call trades gambles for nothing.

On a secondary note, if Halladay can be had in your league, get him now; he’s showing increased K’s and is a gem for leagues which score innings/complete games.

Carlos Beltran for Kosuke Fukudome/Cliff Lee

This is a classic case of someone cashing in on unexpected hot starts to get proven quality. Lee is the undefeated and dominant top-ranked pitcher on Yahoo!, which Fukudome by himself has probably been more impressive than Beltran. I don’t know who offered this deal first, but the price for Beltran was extremely steep; Lee had a horrible 2007 but had always been touted as a potential ace, which makes it more likely he’ll be able to sustain at least 15-win pace.

If you’re the owner of one or more hot starters such as Lee or Nate McLouth, cash in on them accordingly; don’t throw them all away for someone who had both knees tweaked over the offseason and seems to have already reached his peak.

Conor Jackson for Corey Hart

This was a very interesting straight-up swap which went down yesterday. Jackson has recovered from a sluggish 2007 to become one of the biggest waiver-wire steals of 2008. However, the power hitting is still not there, making Jackson seem like a more productive version of Lyle Overbay. Hart has been fine after his breakout 2007, but is lagging a bit in both power and steals.

This trade carries tangible risk and reward for both parties; the owner receiving Hart is banking on Hart being able to at least pick up his stolen bases, while the owner receiving Jackson is praying that Jackson stays as Arizona’s cleanup hitter for the rest of the year. Jackson already has more triples (4) than his past two seasons combined, so the power surge may come sooner rather than later.

If you can’t swing a trade, which bats are still left on the waiver wire?

Milton Bradley, Texas Rangers
Status: Same as usual: good batting, iffy health
Key Stats: .311 - 6 HR - 21 RBI in 35 games
What to Watch For: Suffering from sore shoulder as of May 12
Other Notes: Bradley is the best batter still widely available on waivers. Did we mention that he’s batting in Texas half of the time?

Jay Bruce, Cincinnati Reds
Status: Waiting to be called up to the big leagues
Key Stats: Cincinnati is 17-23; that qualifies as a key stat for Bruce
What to Watch For: Will Jr. or Adam Dunn be traded?
Other Notes: As noted on Imaginary Diamond Sunday, megaprospect Bruce will arrive sooner rather than later; he’s already the number 1 player being picked off waivers on Yahoo! right now.

Andre Ethier, Los Angeles Dodgers
Status: Recovering from poor start to season
Key Stats: .303 average, but .172 against left-handers
What to Watch For: Dodgers’ outfield carousel
Other Notes: With Rafael Furcal’s injury giving Juan Pierre another chance in L.A., Ethier will have to soundly outperform Pierre and Andruw Jones to solidify an everyday job.