There’s nothing more aggravating in fantasy baseball than dealing with injuries. We can’t control when they occur. And we may feel victimized when fate treats the health of our competitors’ rosters more kindly than our own.

But on second thought, injuries provide one of the best tests of real competition. These days, everyone has access to the opinions of experts or can use cutting edge tools like the ones provided by Bloomberg Sports to make roster decisions. But there’s hardly any consensus approach about what to do with a star player who gets put on the injury shelf.

Do you suck it up and do nothing? Do you sell your injured superstar for 80 cents on the dollar? Or might you look at the other side and look to acquire a discounted injured player who can potentially help out down the road?

In looking at a portfolio of assets such as a fantasy baseball roster, and figuring out how to mitigate risk and capitalize on upside, there’s great divergence in strategy. Isn’t that what makes fantasy baseball so great?

BaseballHQ’s Ron Shandler recently pointed out that last year, among the top 276 players, more than 50% ended up missing time — the majority from injuries. This year, more than 10% of players have already experienced injury, including top fantasy superstars such as Jacoby Ellsbury, Brian Roberts, Aaron Hill, Brian Fuentes, Cliff Lee, Huston Street, Jimmy Rollins, Lance Berkman and Manny Ramirez.

The owners of these players have big decisions on their hands: Hold or sell? Other owners may also be tempted into action: Acquire or stay clear?

The decision will often make or break a fantasy season. And as you’ll see by the diagram below, which charts recent trades made in real fantasy leagues, injured superstars like Ellsbury, Roberts, and Rollins are being dealt for widely divergent returns. This is understandable considering that rest-of-the-season projections on these players are hard to figure out with much precision at all:

Scott Kazmir and Zack Greinke have little value commonality these days except for the fact that each brought back Jacoby Ellsbury in trade. Presumably, in one fantasy league, an Ellsbury owner panicked and got whatever he could for his Red Sox outfielder who was just diagnosed with hairline fractures in four of his ribs. In another fantasy league, an Ellsbury owner got a lot more — Zack Greinke, who went behind Ellsbury in many drafts (though not too far behind).

I don’t believe there’s any absolute rule when it comes to what teams should do with injured players except one: Don’t sit still. Many people shrug off any necessity to take action, but that’s a big mistake when the possibility exists of mitigating lost value from injuries or capitalizing on another owner’s frustration. Some of the owners making trades in the above graph have it right.

Here are some more common sense tips:

• Do research and understand the injury: What’s the timeframe for return? What’s the risk of injury setbacks or injury re-occurrences? How long until a player can really rehabilitate and perform up to the usual standard?
• Watch out for misleading news: It’s almost a cliché these days that a player is making “significant progress” in his road to recovery. Reporters have a duty to check up with team management about a player’s status. Rarely do they get an honest response. The spin is usually positive. For buyers, this means tread carefully. For sellers, the moment that news story hits about a player being ahead of schedule on his road to return, this might represent the best opportunity to explore the trade market.
• Correctly factor an injured player’s expected contribution to your team: If your player is going to miss 20% of the season, you might think that means the standard for return in trade is 80%. But keep in mind that even without a trade, you’ll be plugging someone off of reserves or the waiver wire who will produce some. So maybe you’d want a player in return who will give you at least 90% of your injured player’s original value. For buyers, if your potential trading partner doesn’t realize this math, it’s a good investment.
• Measure your team’s need for downgrading risk or upgrading upside: If your team is in the middle of the pack and can’t afford a big hit like a player injury, getting some value in return for an injured player makes sense. If your team is struggling or ahead of the pack with depth to spare, taking on an injured superstar’s upside is also a sound idea. Also keep in mind that a player who is injured can usually be put on the DL, which frees up a roster spot for another player too.
• Be aggressive but cautious: Always assume the worst when it comes to a player’s injury. Professional ballclubs have a lot of money at stake with their players, so organizations are usually conservative in getting a player back into the lineup. If a player is said to be out two-to-four weeks, assume four-to-five.

Finally, I recently expressed some skepticism about whether so-called sell-high candidates like Scott Podsednik are really candidates for trade. Convincing people to move off of long-held perceptions about a player’s ability is usually easier said than done.

Nevertheless, sell-high candidates usually match up very nicely with buy-low candidates. One guy isn’t producing at all. That’s traumatic. The other guy is returning monster value. That’s exciting. This represents some kind of trading match: Scott Podsednik for Jacoby Ellsbury….would you do that deal?