Is Vernon Wells the least Valuable Every Day Player in Baseball?

It's safe to say that the Vernon Wells contract has turned into a millstone that will weigh the Jays down well into the next decade. However the situation would not be as dire if Vernon was still a solid, if unspectacular, major leaguer. However even that faint dream has become a nightmare, as Vernon has turned in an awful season so far. All of which begs the question - is Vernon Wells the least valuable regular in baseball? Calling anyone the worst at anything can be pretty harsh, and such terms are bandied about too lightly. Being the worst is, at the very least, different than being the least valuable, or biggest negative if you will. For example, the worst player in baseball this year was probably the Royals' Tony Pena, who was both a poor shortstop and a poor hitter - he reached base in 7 of 53 plate appearances. However there is a limit to what even teams like the Royals can take, and even they, mercifully, got rid of him. So Tony Pena may have been the worst player in...