The Cardinals traded Jim Edmonds to the Padres in December of 2007. He had 362 homeruns and was a fixture of the Cardinals outfield for the previous 8 seasons. The Cardinals had signed Edmonds to an ill-advised contract extension the previous season during a time that he was clearly on the decline. In return, the Cardinals received a third baseman who had just completed High-A at the age of 24. David Freese had hit reasonably well at Lake Elsinore (.302/.400/.489) though, given his age, he was not a particularly exciting prospect. Four years and multiple major injuries later, he's the Cardinals starting third baseman and an important part of the team.
At the time of his acquisition, the Cardinals had Allen Craig who had consistently hit well during his time in the minors and was still playing third base. Freese wasn't seen as a significant upgrade over Craig; arguably, they were the same player. Depth can yield benefits, as it has in this case, but the departure of a sentimental favorite from the Cardinals for a prospect who looked vaguely familiar was a tough one for some fans to swallow.
In David Freese's first season in the Cardinals' system was a jump from the Padres' High-A club to the Cardinals' AAA Memphis. He endeared himself to fans by hitting 26 homeruns during the 510 PAs in 2008. Freese hit well enough to get some attention for the third base position entering 2009. Injuries would ultimately derail both his 2009 and 2010 but while he's been in the lineup, David Freese has performed impressively on offense.
David Freese is currently hitting .333/.385/.423. His major league line is .312/.370/.419 across 439 PAs (about 2/3rds of a season). Freese has a career .348 wOBA which is above average. What's odd is the way in which Freese has advanced his offense. In some ways, he's failed to live up to his minor league performance. Over 1675 PAs in the minors, David Freese had an ISO of .224 with a slugging percentage over .500. Freese hasn't approached those numbers in the majors.
While power in the minors does not directly translate to power in the majors, it's odd for a player to see such a fundamental aspect of his offensive profile essentially disappear. With Freese's injuries, it's difficult to say what, if any role, those injuries could have played in sapping power. Alternately, as Freese becomes more accustomed to the majors, it's possible that we could see additional power production from the 3rd baseman.
Additional power might be critical to Freese's continued offensive production. With line drive rates and batting averages on balls in play that are likely unsustainable in the long term, Freese will need to increasingly rely on his secondary skills to maintain his offensive performance. With a walk rates that can only be described as as unimpressive, Freese has been reliant on his ability to reach base via hits.
Long term Freese has the possibility to be a 3-4 WAR player based on his performance to date. At age 28, the long term isn't necessarily that long. What the Cardinals will need to decide in the next few years is whether Matt Carpenter or David Freese will be a key component of the club. Matt Carpenter has shown some slightly improved power output (accounting for park) at Memphis while maintaining his high walk rate (18.5%). Carpenter isn't a particularly young player either turning 26 in November. Still, as the acquisition of David Freese with Allen Craig showed, depth is never a bad thing.