Some interesting analysis from Jonathan Scippa on BaseballAnalytics.org:

Tonight, Boston's Carl Crawford returns to where he started his career.  Crawford played nine seasons with the Tampa Bay Rays before signing with the Red Sox this offseason.

The start to his Red Sox career has been anything but easy.  Through his first 40 games, he had hit .205/.243/.280 with just one home run and 31 strike outs.  However, he's managed to slowly climb out of that hole and has raised his line to .246/.279/.393.  At this point in the 2010 season, Crawford was sporting a .296/.346/.465 line.

Here's a look at his SLG% heat maps through June 13 for both this season and last:

Data through June 13 (Click to enlarge image)

Crawford has simply not been as dangerous on pitches in the strike zone this season.  Oddly enough, he's hit the same number of HRs (6) and triples (4) that he did at this point last season.  However, he's striking out at a slightly greater rate (14.2% to 16.9% K-Rate), and walking much less (7.1% to 3.4% BB%).  As a result, his wOBA is down over 50 points from where it was at this point last season.

Crawford has never hit lefties well, but this season he's struggled greatly against them.  He's hitting .159/.216/.280 vs. LHP for a .222 wOBA, compared to a .324 wOBA vs. RHP this season.  In his career, he's put up a .264/.310/.376 line against lefties. 

Tonight, Crawford and the Red Sox face James Shields (TB) who is off to a 5-4 start with a 2.85 ERA with the Rays.  Shields has held lefties to a .232/.279/.379 line this season.  Meanwhile, Crawford has been bashing RHP over the last month, with a .419 wOBA including 3 doubles, 2 triples, and 4 home runs in that span.