One of the hardest jobs for a general manager -- or even a casual fan -- is trying to figure out when a top player or team is about to hit a serious decline. Guess wrong and give up on someone too early and they will burn you for years with another team. Guess wrong and hold onto an in-decline star or keep a fading nucleus together a season too long, and it can put a franchise in a serious rut. But as tough as it is to predict, it can be fun to play the game. And so we offer up this question in light of a truly frightening performance by Johan Santana last night: is the ex-Twin going to hit a very serious wall sometime soon?

The case against: Before that start last night (10 earned runs, including 4 home runs, no ability to locate his fastball), Santana was 3-1 with a 2.08 ERA coming off offseason elbow surgery ... he is a notoriously slow starter who can also throw up a stinker at any point in the season because he's not an overpowering pitcher and does rely on locating his fastball to set up the rest of his pitches. If that goes for one start, he can be give up a ton of runs in a hurry ... He just turned 31, an age not associated with burnout. His arm should have several good years left.

The case for: The elbow problem is the biggest factor. A pitcher that relies so much on things falling into place can't afford to be out of sync. ... His WHIP (walks and hits per innings pitched) has gone up every year since 2004, while his Ks/9 innings, which were usually between 9 and 10 with the Twins, have never been higher than 7.9 with the Mets. ... There have been questions about his velocity.

This is Year 3 of the six-year deal he signed with the Mets after the trade from the Twins. The first year was outstanding; the second year was going pretty decent until the elbow injury; the third year was going pretty well until yesterday. What will the rest of this year and the final three bring? So much depends on health, but we would hardly rule out a Pedro Martinez-esque arc and drop.