Fantasy baseball: How do trades affect your team?

The trading deadline has a big effect on fantasy baseball leagues, especially mono-leagues. Here's a look at the impact.

Roy Oswalt (Phillies, SP): Oswalt pitched very well for the Astros with his highest K/9 since 2002, but had just six wins. He should be in line for more wins on a better team with more run support.

J.A. Happ (Astros, SP): Happ was overrated to begin with and moving to the Astros hurts his value even more. The lefthander has control issues and doesn't get a lot of strikeouts. Don't let last season's 2.93 ERA or his six scoreless innings in his Astros debut Friday fool you. Happ is only an option in NL-only leagues.

Jorge Cantu (Rangers, 1B/3B): Cantu hasn't done much since April, but the move to Texas gives him a boost. He moves to an excellent lineup and should get more RBI opportunities and hit a few more home runs. He'll certainly help AL-only leagues. The Marlins' Logan Morrison and Emilio Bonifacio gain value in NL-only leagues.

Lance Berkman (Yankees, 1B): He had arthroscopic knee surgery in March and started off slowly. He has picked it up with eight home runs and 32 RBIs since June 1. The move will help Berkman as he goes from a putrid offense to an excellent one and will be the DH. He'll be a big addition in AL-only leagues.

Brett Wallace (Astros, 1B): His value obviously goes way up because he is finally in the majors. Wallace was batting .301 with 18 home runs and 61 RBIs at Triple-A in a hitter-friendly park in Las Vegas. Wallace started at first base yesterday and should see a lot of playing time. A pickup in NL-only leagues.

Matt Capps (Twins, RP): Capps' value doesn't change since he is still closing. Jon Rauch loses value in leagues without holds and Drew Storen, Tyler Clippard and Sean Burnett are expected to split closing duties in Washington. My money is on Storen.

Jhonny Peralta (Tigers, 3B): No major change in value for Peralta, who has shown the power he displayed two years ago. The trade gives Jayson Nix some value in AL-only leagues since he'll get time at third base for the Indians.

Miguel Tejada (Padres, 3B): Tejada has no power and the move to spacious PETCO Park isn't good. He's not useful in mixed leagues.

Chris Snyder (Pirates, C): Snyder strikes out a lot and will be a drain on your batting average, but he has power with 10 home runs in 195 at-bats and hit 16 in 334 at-bats in 2008. He'll play every day and Ryan Doumit will move to the outfield when he returns from the disabled list.

Jake Westbrook (Cardinals, SP): Low strikeout rate, gets groundballs and now under the tutelage of Dave Duncan. Sounds like a good gamble in NL-only leagues.

Ryan Ludwick (Padres, OF): Has power and while PETCO Park isn't a hitters' park, it hurts lefthanders more than righthanders. Cardinals outfielder Jon Jay gets a boost in value in NL-only leagues.