The signing solidifies the back end of the Pittsburgh bullpen, as Grilli was far and away the Bucs' best relief pitcher last season. It remains to be seen whether that achievement will earn him the closer role in 2013.
Of course, the Pirates already have an "established closer" in Joel Hanrahan, who compiled 76 saves during the last two seasons. But Hanrahan is expensive, and keeping both Hanrahan and Grilli would cost the Bucs around $10 million in 2013. Plus, beyond saves and ERA Hanrahan actually didn't have a very good season in 2012.
Hanrahan's walk numbers are somewhat frightening, especially given his inability to consistently throw strikes before his 2012 breakout season. Hanrahan has great stuff and strikes guys out, but so does Grilli.
Grilli is also a more cost-effective option for a team that has never spent a substantial portion of its payroll on relief pitching. Neal Huntington has instead preferred to piece his bullpens together, and he has been quite successful at this. Grilli, who the Pirates literally acquired for nothing from the Phillies during the 2011 season, is the perfect example.
The Bucs are once again capable of putting together a strong bullpen on the cheap, with talented pitchers like Bryan Morris, Justin Wilson and Victor Black waiting in the wings. There have been rumblings that the Pirates are in fact shopping Hanrahan, and this wouldn't be a big surprise given the circumstances.
But trading Hanrahan is all about capitalizing on a valuation gap between how the Pirates and other teams view closers, and it appears that this gap may be rapidly closing. It may be the case that closers bring bigger returns when teams feel like they need them in the heat of a playoff chase, or it may just be that front offices are becoming more analytical and understand the limited value of relief pitching.
Whatever the case, if the Pirates cannot address a need (outfield, shortstop, or starting pitching) by moving Hanrahan then it is tougher to make the case that they should do so. Perhaps the $7 million or so that Hanrahan will make next year could be better spent elsewhere, but the Bucs will need to identify actual targets to spend that money on.
The Pirates will likely continue to shop Hanrahan, as Grilli's presence makes him a luxury. But it remains to be seen whether they will find the deal they are looking for.