When we last checked, Mark DeRosa was ranked as a Type B free agent as a member of the Indians. At that time, he was grouped with the American League second basemen, third basemen, and shortstops. His 61.7 score put him about ten points below the lowest Type A in the group, Melvin Mora.
Now a Cardinal, DeRosa will be ranked with the NL 2B/3B/SSs by Elias after the season. I just ran the numbers with DeRosa as part of this group, and his score jumped to 67.9. He's still a Type B, but is now only three points from the lowest Type A in the group (Troy Tulowitzki at 70.9). The seven stats that go into DeRosa's ranking: plate appearances, batting average, on-base percentage, home runs, runs batted in, fielding percentage, and total chances at his designated position.
So the Cardinals may have received more than just three months of DeRosa; they also could end up with one or two draft picks as free agent compensation. For that to happen they'd need to offer him arbitration, then see him decline and sign elsewhere. Offering arbitration means the Cards would risk DeRosa accepting and landing a one-year contract for 2010 north of his current $5.5MM salary. As Ken Rosenthal alluded to today, some teams might prefer certain free agents ranked as Type Bs so that there would be no deterrent for another club to sign them.