This has become a popular strategy among fantasy owners today. It's fairly simple, target the player you think your opponent will go after. The idea of course being that you prevent that owner from getting a potentially big game from a hot name on the waiver wire. This strategy is no more prevalent than during the bye weeks, though it does occur at any time in the season. This strategy is frequently used, but is it really effective? Let's take a look at an example that actually occurred in one of my leagues this year:
Team A faces Team B this week. Team B has its stud QB on a bye and his back-up QB is injured. He needs to pick up a QB off the waiver wire to field a full team. Team A has a higher waiver priority, however. Team A isn't really interested in anybody on the wire, but he notices that there aren't too many appealing QBs on the wire and his opponent is short a QB and must pick one up. Team A considers his options and decides to "block" his opponent. He grabs the best QB. Team B is not happy and is forced to take a gamble on a less than thrilling option. So how did it work out?
Team B defeated Team A by 6 points. Team A already had 2 QBs, but picked up David Garrard to block his opponent. David Garrard had a great match-up against the Titans and was far and away the best option for anybody needing a QB for a week. Team B reluctantly picked up Matt Stafford for the week. Well color everyone surprised when Garrard put up a whopping 3 points that week while Stafford put up 15. Team B actually sent Team A an email THANKING him for stealing Garrard because he said that's who he had intended to claim. Team A was irate, but he did it to himself.
This is an example of why this is a flawed strategy. Team A determined here that Garrard was the logical pick-up, but it didn't work out. It cost him a win. And this is an example where the targeted player was clear cut. There was a case earlier in the year where someone in my division wanted me to beat this one guy, so he picked up Favre (facing DET) so the guy I was playing couldn't have him, thinking he was doing me a favor. Wrong. The guy I was playing ended up picking up Orton against NE, and Orton put up 22 points while Favre put up only 14. I lost by 4. Thanks guy. I appreciate the help.
We can also take a look at this from a cost/benefit point of view. When you are making a decision to block another owner, you are using YOUR own assigned values to the players available. You are assuming he values the players the same way you do. This assumption is flawed. No two owners assign the same values to players. While you think you may be taking away his best option, he may have never even considered that guy anyway. Therefore, you just wasted a waiver pick on a guy who has zero value to your team, and in the process passing on guys who may be of use to your roster. Also, how much of a difference do you think picking up a player will ACTUALLY make. Over the long haul, you can maybe expect a 2 or 3 point difference. That's hardly worth passing up an opportunity to improve your team.
There are just not enough rewards to make "blocking" an effective strategy. It can just as easily blow up in your face as it could help you. You risk passing up potentially helpful players for a player who has no value to you. It's just too risky. Fantasy sports are about making the right decisions. It's ALWAYS the right decision to add a player if you think he will help you out, regardless of whether or not he actually does. It's SOMETIMES the right decision to add a player you think your opponent needs because you don't know who he actually does want and even if you do guess correctly, your gambling his 2nd choice doesn't have a better day than his 1st choice. The "blocking" strategy sounds great in theory, and it may work a few times. But in reality it is a losing strategy over the long haul.