Lewis had reached the end of a minor league rehab start, and as such the Giants needed to either open up a 25-man roster spot for him, place him on waivers, or trade him. The Giants will actually be receiving either cash considerations or a player to be named later.
Lewis is pretty clearly a Major League quality player. In 1,048 plate appearances in the major leagues since 2006, Lewis has recorded a .277/.355/.420 line, showcasing good plate discipline and slightly below average power. His 109 wRC+ suggests an above average player. 2009 was a down year for Lewis, however, as his ISO dropped from .158 to .132. As a result, his wOBA and wRC dropped to .327 and 98 respectively, the first year in which he has been below average in either statistic. The projection systems see him as slightly above average this year, and ZiPS in particular expects a return to 2008 levels.
Defensively, both UZR and +/- are fans of Lewis, despite his poor reputation among Giants fans in Tom Tango’s Fan Scouting Report. Both systems have Lewis between +9 and +11 over his 326 game career, which would still make him a below average position-neutral defender over 150 games.
Overall, not only does that make Lewis an MLBer, but it makes him nearly an average player. There is no way that Lewis is only the 6th best outfielder on the Giants roster. Aaron Rowand is projected to have a similar or worse year. Nate Schierholtz has similar projections. Andres Torres is 32 and projected to be well below average at the plate by both CHONE and ZiPS – Marcel’s projection is only operating on 181 ML plate appearances since 2007. Eugenio Velez has put up 201 games of replacement level baseball in his career so far, and the projections don’t see improvement in his future – only a data-starved Marcel projects a wRC+ greater than 90.
Still, it’s possible that the Giants know something that isn’t in these stats. Perhaps UZR and +/- are completely wrong on Lewis’s defense. Maybe he’s a clubhouse cancer, or maybe his injury troubles are worse than they seem on the surface. Even if all of those things are true, though, there’s no way the Giants found maximum value for Lewis’s talents. Hitters with a .355 career OBP and a walk rate over 10% don’t just grow on trees, and especially not those still drawing a pre-arbitration salary. Somebody must have at least had a grade B prospect they would have been willing to part with for Lewis, and if not, then there’s no reason to get rid of him when Torres and Velez are still on the team.
For the Blue Jays, this is an immediate upgrade over Jose Bautista, a player projected for a mid-90s wRC+ and poor defense in the corners – a combination that results in roughly replacement level production. The Jays have acquired a player who could potentially become an asset and a contributor for essentially no cost. The risk is minimal, and a potential reward is there. For the Blue Jays, this is a no-brainer, and for the Giants, it’s a head scratcher.