This time last season the Mets' ace was Tom Glavine, so we would have been watching a Glavine/Ben Sheets matchup this afternoon. When healthy, Ben Sheets is a prepoculously good pitcher with overpowering stuff and impeccable control. Johan Santana has slightly better stuff and slightly worse control, but considerably more healthy and therefore significantly more valuable.
Sheets will be a free agent this offseason, and would probably be looking at a $100 million contract if he didn't have such an expansive medical history. He has a career strikeout-to-walk ratio of almost 4-to-1, and has struck out close to eight batters an inning since 2002. He hasn't always had health problems, though. From 2002-2004 he averaged more than 220 innings pitched. Unfortunately, from 2004-2006 has has averaged around 130. He will be part of a pitching-heavy free agent class that also includes C.C. Sabathia and Oliver Perez and may include Pedro Martinez, A.J. Burnett, and others. Given Santana's cost I think it's safe to say the Mets are probably out of the Sabathia sweepstakes, but if Sheets can prove that he is healthy this season he might be a less-expensive alternative who would require a smaller commitment in both money and years.