Over the weekend, new Yankee Alfonso Soriano paid early dividends with a home run and a walk-off single against the Rays.  It was a big win for the Yankees who, even with the victory, remain 7.5 games back in the division and 7.0 games behind the second-place Rays.

Brian Cashman was probably correct in his assessment that Soriano will help the team, if only by keeping Vernon Wells and his .283 OBP on the bench.  However, the 18 home runs and 10 stolen bases that made Soriano attractive to teams like the Yankees are counterbalanced by flaws that do now show up as readily in traditional counting statistics.

Since 2009, Soriano has cost the Cubs an estimated 43 runs with his poor defense, the fifth-worst total by an outfielder in that time.  More subtle is his poor baserunning, a limitation belied by his stolen base totals.  Among players with at least 30 stolen bases since 2009, Soriano has the 10th-worst Net Gain–a comprehensive measurement of baserunning that includes success rate on moving first to third, second to home, and first to home on hits as well as stolen bases.

Of course, a right-handed bat with 30-homer potential is still a valuable addition for the Yankees.  It’s probably not worth $19 million per season, however, which Soriano will make through the 2014 season.  The Cubs will pick up a lot of that salary, but if the Yankees are as desperate to stay below the Luxury Tax threshold as media reports indicates, one wonders if they could spend their money and prospects more efficiently.