How they'll fare in their new homes

Projecting player performance is a funny thing. The bottom line is we don't know. We may think we know. We may hedge and say we think we think we know, but at the end of the day, we don't know. However, we can make a very educated guess. But in order to make an educated guess, we must be, well, educated. The more that we can know the better.

Below are twelve impact players that are changing teams, most in new divisions with some switching leagues. We have a pretty good idea how they would have fared in their old venues. Reviewed are some of the new challenges and obstacles that may impact their performance and production, both good and bad this season. At the end of each player's evaluation, a judgment will be made: HELP, HURT or NO CHANGE. Remember, a conclusion of NO CHANGE, while not so compelling, tells us information just as valuable as HELP or HURT.

Before delving into the analysis, here is a brief explanation of some of the methods that will be employed in each evaluation.

Park factors: Some venues favor hitters and others pitchers. This can be quantified and a park factor can be determined by comparing how each specific park plays relative to a neutral park. Park factors can be calculated for any statistic and can be broken down into left-handed factors and right-handed components. Because of inherent elements that fluctuate year to year, park factors are conventionally presented as an average of the past three season's worth of data. Not all player's will be impacted by the park factor exactly as dictated by the number, but most at least trend in that direction.

Advances in data collecting and technology in general have elevated the concept of a park factor to a new level. One tool on Katron.org collects MLB Gameday data on every batted ball in play and allows the user to overlay one park onto another, and then focus on batted ball types individually or collectively for every batter and against every pitcher. The utility here is hitters' batted balls at his previous home field can be laid on top of his new park to get an idea how many fly balls would have been, or not have been homers. The same can be done for pitchers. Please realize this should not be treated as verbatim. The distances are inexact and climate conditions were not factored in. Another tool that indeed does factor in weather conditions such as temperature and wind along with ball trajectory and speed to determine a normalized home run distance is the ESPN Home Run Tracker. Taken in concert, while the results will not be perfect, it can be gleaned if a change in venue will be beneficial or detrimental, at least in terms of home runs hit for a batter or allowed for a pitcher.

Interleague statistics: Even though the number of interleague games each team plays each season is small compared to their whole schedule, some veterans have participated in almost a full season's worth of interleague games. Looking at those numbers may afford at least an inkling of how the player might fare when crossing leagues. Also, keep in mind what Bill James teaches us about small sample size and that is that extremes can be significant even in a small sample.

Another application of interleague statistics is directed towards pitching and that is the effect of losing or gaining facing the designated hitter, as there are different average strikeout and walk rates for National League and American League hurlers.

Quality of opponent: If, on a collective basis, a hitter is slated to face weaker pitching, then his numbers are likely to improve just as they apt to decline if he squares off against overall better pitching. Similarly, if a pitcher is going to be facing, on the whole, weaker hitters, his numbers should improve, and vice versa. While it is true that there is player movement every season, skewing this sort of analysis, there is still ample roster stability and teams play a preponderance of games within their division to at least see if the quality of opponents is vastly different, fulfilling Bill James' rule of extremes.

Quality of New Team: With respect to pitchers, while it is true that wins are fickle and there are always exceptional cases where a pitcher's won-loss record is not indicative of the manner he pitched, it is fair to say that the probability a starting pitcher earns more wins improves if he moves to a team affording him better run support and/or a superior bullpen.

With regards to batters, though the notion of lineup protection influencing one's slash line has been proven to by a myth, there is definitely something to be said for the quality of the surrounding cast in terms of runs and RBI production. Additionally, the more runs a team scores, the more times the lineup turns over and the more trips to the dish a batter receives over the course of the season.

With that as a backdrop, here are twelve prominent players that are wearing a new uniform this season and a look at how their skills and performance may be altered in their new digs.