General fatigue would normally have been an issue if it was an early afternoon game but luckily for the teams it's the ESPN Sunday night game starting at 8pm EST so they have got plenty of time to recharge the batteries - so the question is more relevant to the bullpen issue.
The Mets used 8 relievers and the Cardinals used 9 - more importantly, 4 for the Mets pitched 2+ innings as opposed to 3 for the Cardinals. I'm too lazy to look at how often each reliver has pitched in the last few days but we can be sure that anyone pitching 2+ innings tonight will be out for tomorrow. Then we look at the starting pitchers and who is more likely to place a burden on the bullpen.
John Maine is starting for the Mets after back to back poor starts to kick off the season (losing 2mph on his fastball isn't helping matters) averaging 4 innings per start. In 2009 he averaged 5.42 innings per start, 5.60 in 2008 and 5.97 in 2007. Adam Wainwright is up for the Cardinals who has averaged 7.5 innings over his first two starts; 6.85 in 2009, 6.6 in 2008 and 6.31 in 2007.
The most important statistic is seeing how much the line for tomorrow's game moved as today's game progressed - i.e. has this already been factored into the line.
