So much can change over the course of one MLB season. Players with expiring contracts and those coming off uncharacteristically strong or poor performances have the most to gain and lose in 2013.
We can only observe results. Therefore, it's the responsibility of those individuals to make subtle changes in their preparation to ensure that everything goes smoothly under the bright lights.
Avoiding injury is also particularly important for the following guys. If a player needs to rebound from a lost season, he'll want every opportunity to prove that it was a fluke. Likewise, hot commodities could suffer financial losses if they can't validate a breakout year.
The baseball world will certainly be keeping a close eye on these men.