It was a crazy weekend leading up to the Winter meetings. Yesterday as I was planning and writing this post, the Adrian Gonzalez trade was off and then back on, in between the Nationals signed Jayson Werth to a huge deal, and then the Brewers and Blue Jays swapped Shaun Marcum and Brett Lawrie. Because of the timing of these developments I didn't include these transitions here, and anyway Rich had a great take on the Gonzalez deal and lots will be written about the moves anyway. Instead I focused on two smaller deals that happened over the past couple days: the Yankees re-signing Derek Jeter and Mariano Rivera. Thought neither was terribly surprising, I wanted to check in on each player's 2010 and what they portend for 2011 and beyond.

Derek Jeter

Of course there is a big back story in these negotiations, but in the end is played out pretty much as everyone expected it would. Jeter re-signed with the Yankees for three years and $51 million dollars. Probably a bit over the value he will give them, but in the ballpark for the Yankees and Jeter.

With Jeter signed we can turn our attention to his performance. Although 2010 was his worst year since his rookie season (both fWAR and brWAR see it that way), 2009 was his best year since 1999 (again fWAR and brWAR agree on that). No one expects another 2009-like, six-win season, but a rebound from 2010 is perfectly reasonable. A big question looms of how much longer Jeter can stay at short, but here I wanted to check in on his offense. His near career-worse WAR was driven by his first sub-100 RC+ (under league-average offense) since his rookie year.

The big culprit here was his career high 65.7% GB rate, that lead the league by a big margin, and was the highest full-season rate since Luis Castillo's 66.7% in 2007. Jeter has always hit a lot of ground balls, but hitting nearly two-thirds of his balls in play on the ground makes it very hard to hit for much power and results in tons of GDPs. Here I show Jeter's GB% base on pitch height for 2010 compared to 2007-2009, with standard error indicated.

For a given pitch height in the strike zone Jeter hit about 10% more ground balls in 2010 compared to the previous years. If Jeter is going to regain some of his offensive value it is going to have to start with getting his GB% back to a reasonable level.

Mariano Rivera

Rivera signed a two-year $30 million dollar contract, and said that it might be his last. There is not much new to say about Rivera on the pitchf/x front: no other player has been more pitchf/x-dissected . For those who might have missed a couple recent additions: a cool by-count breakdown by Albert Lyu, In Depth Baseball's look at Rivera, and a great New York Times video. The take-home message of all that is Rivera routinely hits both edges of the plate without hitting the heart against both RHBs and LHBs with his cutter. No other pitcher has his ability to pitch strikes without getting the fat of the plate.

Although his overall numbers have been amazing forever, his strikeout numbers took a little dip this year. Digging into it a little more it looks to me like the whiff rate on his cutter versus LHBs was the big culprit (17% from 2007 to 2009, just 9% in 2010). Here is what the whiff rate looks like based on the horizontal location of the pitch.

You can see how the whiff rate is high on the edges of the plate (where he pitches the most), but that in 2010 it was lower on both sides, and much lower away. This could just be noise, a one year fluke, but age has to catch up to everyone, even Rivera. But even if his strikeout rate is a little lower Rivera will most likely still be a great pitcher in 2011 and 2012 (as he was in 2010). His other skills are just too good: he doesn't walk many batters, gets lots of ground balls, and as a walking counter-example to DIPS has the ability to depress his BABIP and HR/FB (career rates of .273 and 6.3%).

So as expected going into the offseason Jeter and Rivera re-signed with the Yankees, and anything else would have been just wrong. Now we will see how these two aging Yankees perform over the next couple years.