Rivera's understudy will be tested in October

Let's get one thing out of the way. NOBODY is replacing Mariano Rivera. Not David Robertson. Not anyone. Someone else will close games for the Yankees in 2012, but they won't be his REPLACEMENT.

50 some odd innings in a season isn't hard to replace.
Nor is it hard to find someone to secure 30 some odd saves a year. Hell, Kevin Gregg did that year in and year out and teams couldn't wait to dump him. If your ERA is around 4, then most times you pitch an inning with your team up by 3 or fewer runs, you'll keep the team from taking the lead. Do that 30 times and boom, you have big save totals.

But Rivera had a quality that can't be put into numbers.
Watch teams in the 8th inning against the Yankees in a close game.

Teams HAD to score in the 8th to tie it because they knew that Rivera wasn't going to lose it.

He was a difference making closer, that most rare of commodities.

But as we know, that isn't where Yankees are judged.
A great regular season can be totally nullified by a bad post season. Ask A-Rod who won 2 MVP titles but was showered by boos in both those years when his bat went AWOL in October.

And likewise a memorable post season can redeem a mediocre regular season.

El Duque Hernandez rarely put up great regular season numbers but came up big in October. Aaron Boone and Luis Sojo were marginal players in the Bronx but drove in Series winning runs and will always be considered to be Yankee heroes.

Rivera, whose regular season accomplishments had no equal, somehow was better in October.
8-1 record.
Lowest ERA in post season history (0.70) and had went 42 for 47 in post season save chances. Throw in two post season MVPS and more World Series clinched than anyone in history and you have almost a perfect resume.

Think of that. He blew 5 leads in 32 different post season series.

You think David Robertson, a talent pitcher to be sure, will come anywhere close to that?
You think Yankee fans, who have been spoiled to accept not only October appearances but also success in the 9th inning, will adjust well than a slammed door in the 9th?

Even if Robertson saves 40 games between now and the end of September, it can all be thrown in the dumpster with one bad inning in October.

No pressure.