Most of you know that Ellis is a very good defender. Can't hit much, but he's good with the glove. What a lot of you don't know is that Ellis is not just "very good" with the glove, he's one of the best defenders in the majors, and his defense is worth a whole heck of a lot.

I've heard people on AN say that the A's need more offense, not defense. That's such an ignorant statement it makes me cringe. A run saved is a run saved. The balance between offense and defense is overblown. You win games by scoring more runs that your opponent runs. You can do that just as well by preventing runs as you can by scoring them.

Okay, let's get down to numbers. According to MGL, Ellis has saved 23, 12, 26, and 21 runs with his glove from 2005-2008. Based on this, it's not unreasonable to guess that Ellis is worth +20 runs with the glove alone. Almost no players are actually that good with the glove, so let's say Ellis got lucky and that he's actually +15 with the glove.

Ellis wasn't much of a hitter last year, and his endless parade of popups was positively Byrnesian. But his Marcel projection suggests that he will be an exactly league-average hitter going forward. (Those of you who say, "but he hit .233 last year!" will be subject to Nico and his goat. Staturdays are for intelligent discussion, and if you can't keep up then I'd rather you not participate.) Ellis is positively average with the bat.

So, offense and defense combined, Ellis is +15 runs compared to all other players, or +1.5 wins. But that's not all: Ellis is a secondbaseman. I've talked before about positional value before, so I won't rehash it again, but that adds another 0.25 wins to his ledger. And I've talked about replacement level before as well, which adds another 2.5 wins. That means that, all told, Ellis is worth about 4.25 wins above replacement over a full season.

Now, Ellis is coming off surgery and he's getting older, so let's say that his defense and offense both fall off and he misses time next year. Knock over a win off that 4.25 figure, and you get 3 wins above replacement. I'm kicking him down a lot of notches, but I'm being pessimistic here.

Players who were worth about 3 wins above replacement this year: JD Drew, Jack Cust, Miguel Cabrera, Derek Jeter, Justin Morneau.

The A's just signed Justin Morneau to a two-year contract for $11 MM. And, if it works out, the A's have an option for a third year at $6 MM. And I'm being pessimistic about Ellis's future performance. What a ridiculous steal.

Did you know that the going rate for a win on the free-agent market is about $4.8 MM dollars? The A's should be tryin to pay less than that, obviously, since they keep a small payroll. Let's say the A's want to target $3.5 MM per free agent win. They should be paying Ellis at least $10 MM next year.

Assuming Ellis gets worse every year from here on out (to the tune of -0.5 wins per year), assuming no salary inflation over the next three years (almost certainly untrue), Ellis would be worth at least $36 MM on a three year contract in the open market. The A's got him for less than a third of that, and hedged their risk by making the third year a team option. This is almost unfair to Ellis.

How could this go wrong for the A's? Well, let's find the breakeven point. I'm already assuming that Ellis is a +15 run fielder instead of +20, and that he's -5 runs as a hitter instead of +0. So, starting from this pessimistic viewpoint, let's assume that Ellis is even worse.

Knock his fielding for 2009-2010 to +10 and +5 (from +15 and +10). Knock his hitting down to -10 and -15. So, by 2010, he's one of the worst everyday hitters in the majors (like Willie Bloomquist bad) and just barely above average with the glove. That gives the A's 4.5 wins above replacement for two years. Now say Ellis misses a third of the games the A's play. That's now 3 wins above replacement over two years. That would cost, on the free agent market, $14.5 MM, or about $7 MM per year - less than what the A's signed Ellis for.

So - if Ellis is terrible with the bat, sees his fielding fall off a cliff, and misses a third of each season, the A's come out even.

One final thing. There was discussion that the A's have depth at this position because of Cliff Pennington, Eric Patterson, Adrian Cardenas, and Jemile Weeks. The former two are ready for the majors now, but don't project to be anything close to Ellis as a player. Ellis is a star player. Even at the major-league minimum salary, there's no way that Pennington and Patterson are worth playing over Ellis. Cardenas and Weeks are no locks to stay at second base, and while both might be stars like Ellis one day, that day is certainly not until 2010, after which the A's have the option of terminating MaEl's contract.

To his credit, Ellis likes it in Oakland, apparently likes the fans, and is showing loyalty to the organization that stood by him while he rehabbed a potentially career-ending injury. He's throwing away tens of millions of dollars to do that. Whether it's because he's stupid or noble, I don't know. All I know is that A's fans get to benefit.

I'm so happy that I'll get to watch Ellis for the next few years, and you should be too.