In every sport as the season moves along handicapping adjustments need to be made however in baseball the adjustments are more pronounced in my opinion.
The weather heats up the ball travels farther scoring goes up. The games become more and more important the pressure increases especially with the added wild card. More teams will remain in the race longer teams and players that are not used to playing important games in September. Look for teams that have the experience dealing with races coming down to the wire as well as managers that have been through the wars.
Bullpen arms become worn down. Look at starting pitchers who are crossing a threshold of innings pitched that they have never done before in a season. Pitchers that were effective in April in May often run out of gas.
The trade deadline will have come and gone and the stronger get stronger as teams out of it have salary dumped key players to the contenders. You will generally lay more juice in the second half but in most cases, it will be warranted just pick your spots properly.
Conversely teams that are out of it will often play call ups and prospects. Just because that is the case does not mean you cannot find spots to bet on those teams. Those players have no pressure go out having fun enjoying playing the spoiler. Remember just because a team NEEDS to win does not mean they will. Secondly teams that NEED to win in all sports are usually over priced by the markets. How often in all sports do you see a team that has been awful all year out of it for some time go on a misleading big winning streak to close out the year. There is often value riding those teams because of stale market perceptions.
Put very little weight on year-to-date numbers. What a team or a pitcher did in April is totally irrelevant to predict what will happen in September.
Baseball for some bettors is very difficult to determine value. We deal exclusively with money lines instead of point spreads. Just like the stock market buy low and sell high. The key which is what we get paid to do is make accurate valuations.