Carlos Lee and Kevin Mench

A week ago, the Rangers and Brewers swapped leftfielders and a few other players. Texas acquired Carlos Lee and minor leaguer Nelson Cruz for Kevin Mench, Laynce Nix, Francisco Cordero and a minor leaguer. At the time, I thought Cordero (an A reliever most of his career) was the key to the deal, and I called Mench a “poor man’s Lee.”

Most Internet posters seem to think that the Rangers got the best of this deal. For instance, ESPN’s Keith Law opined…

Unless the Brewers have a second move in mind involving Mench, Cordero, or Turnbow, it’s hard to see how this is a good return on arguably the most attractive position player on the trade market.

But the erstwhile MGL, in this thread feels that once you include fielding and baserunning, Mench is actually a better player than Lee — and he’s cheaper to boot. So I thought it would be fun to compare the two. Let’s start with a basic Runs Created graph, showing each player’s Runs Created over their career:

You’ve got to say that the Brewers picked a fine time to trade Lee, who is having the best year of his career and will be a free agent at the end of the season. Mench isn’t having as good a year, but his production was very similar to Lee’s prior to 2006.

Breaking down their stats a little, Mench and Lee have exhibited the same level of on-base skill throughout the years…

..but the difference between the two this year has been their power.

Almost 18% of Lee’s outfield flies have been home runs, compared to a previous average of about 13%. Given his track record, I’d say it’s highly unlikely he will maintain that rate for the rest of the year.

In comparison, Mench has kept his home run/outfield fly rate at about 11% (aided by his old home park), but his 2006 slugging decline is more related to a higher groundball rate (42% vs. a previous career average of 36%). That could be a disturbing trend, because changes in batted ball rates can signal abrupt changes in a batter’s true performance. At least, that’s my hypothesis. Maybe I’ll test that someday…

If you had compared Lee and Mench at the end of last year, you might have said that Lee has a slight edge in power but not much else. Does this year–particularly Mench’s increase in groundballs–change that assessment? I will leave that to you.

As for fielding, Mench ranked 15th among leftfielders last year and Lee ranked 23rd, according to John Dewan’s Fielding Bible. Lee truly looks like a bad baserunner, however. The Hardball Times Annual gave him -2.8 baserunning runs and Mench received a positive 2.2.

Overall, there appears to be about a 10-run edge for Mench in fielding and baserunning (equal to one win) and prior to this year, you might have rated Lee and Mench relatively even in batting prowess. Add in the fact that Mench is younger and won’t be a free agent for two years, and you might actually believe that Mench really isn’t that “poor” a relation to Lee. In the meantime, watch his groundball rate.