Pick a pitcher. Say, Vicente Padilla. He’s had a pretty average career. Career 4.46 FIP, which is a pretty good estimate of what we like to call his “true talent” ERA. Put an average defense behind him, in an average park, and he’s a 4.46 ERA pitcher. Put him in PETCO Park, he might put up a 3.80 ERA. Does that mean that he’s worth more, now that he’s pitching in San Diego? No, not really, because you have to consider the context. San Diego can still find better pitchers, and teams that would trade for him should not consider him more valuable because his ERA is higher. He’s still a 4.46 true talent ERA pitcher. Webb is a back-end starter at best, likely not worth much over replacement. Italiano is destined for the bullpen, and bullpen pitchers have very little value. Gallagher’s advantage over Hairston is the fact that he’s under team control for longer. Hairston has shown the potential to play at or above a major league average level, which is worth 10 million dollars plus. He’s being paid 1.5 million this year and is under team control for the next few years. Gallagher may have the potential to beat that, but Hairston’s major league track record makes him a valuable commodity right now, and Gallagher’s recent history of injuries and the fact that he was beaten out in the A’s rotation by 5 other nobodies seems to suggest that he’s not a ML average player, even considering potential.