Baseball Prospectus' Take:
"Beltre is an excellent defender and in most seasons an acceptable hitter, but he's not smart enough to wear a cup. The world found out more than it wanted to know about Beltre's privates when a bad-hop grounder, with almost Darwinian precesion, scored a bull's-eye on August 12th...Pitchers preyed on his weakened [shoulder], challenging him, and his walk rate nearly went the way of his testicles...Safeco Field has a strong prejudice against right-handed hitters...[Beltre hit] .276/.326/.485 with a home run every 24 at-bats on the road...Beltre will never again finish second on an MVP ballot, but he's young enough to recapture some of his old luster playing in Fenway."
I've already professed my love here and here (but of course MLB has taken the video of his defensive highlights down so you'll just have to wait until the season starts to see his brilliance; I will save my rant against MLB's video rules for another day), so at the risk of coming off as a stalker I will keep this brief and professional.
We already know his defense is going to be sublime. The huge question is what will he bring to the offense?
This is the first true hacker the Sox have had in a prominent role in quite some time. Beltre does not work the count and does not take a whole lot of walks. His OBP is batting average driven. It would be nice to think and hope that the Sox organizational philosophy will rub off on him a bit and he can bump his walks up over 50 this year, but this guy has been in the league since he was 19 (!) and pretty much what you see is what you get. The room for upside lies in his transition from Safeco Field, one of the toughest parks for right-handed batters, to Fenway, one of the most inviting.
If Beltre can learn to pepper balls off the wall this year he could turn in a really good offensive season. However, if we look at his splits last year, this may be unlikely to happen. According to Fangraphs, Beltre only hit 22% of his fly balls to left field in 2009. If he repeats this trend this year then that inviting Monster will go to waste. However if we think about this a little more and look at another number things start to look better.
First, we can infer that Beltre knew how hard it was to hit with power at Safeco having played there for 5 seasons. Knowing this, he could have begun to tailor his swing for the ball park, focusing on lofting balls to the opposite field.
Second, we can also look to his Home Run per Fly Ball percentage and see that Beltre hit 16% of his flyballs to LF for home runs.
If we put these together we can reasonably think that Beltre knows when to turn on a ball based on what he can do with it. If he brings this knowledge and ability to Fenway, he may be more prone to taking the ball to left and with his past ability to hit for power he could seriously exceed his 17 homer projection, assuming his shoulder (and testicles) is healed.
There are a lot of "ifs", "coulds" and "assumings" with my new man crush. But the man was brought here to own the left side of the infield and that is a fairly sure thing if there ever was one. So, anything he can provide us on offense we really have to view as creamy, thick, delicious gravy. Shit, so much for being professional.