How Much Does Zack Greinke Improve the Angels?

On Friday night, the Angels landed the big prize of this trade deadline season, acquiring Zack Greinke from Milwaukee in exchange for shortstop Jean Segura and pitchers Ariel Pena and John Hellweg. Given all that the Angels have invested in their current club, pushing the team forward with another big upgrade makes sense on paper. In fact, given that they’ve cut the Rangers lead down to five games in the AL West, the value of a marginal win for Anaheim is extremely high, as the difference between a division winner and a wild card is enormous.

So, acquiring an impact player makes sense given the Angels position in the standings and their desire to win in the short term, but in looking at the specifics of the Angels roster, I wonder if they won’t realize a smaller improvement than one might expect from a team acquiring a top flight starter.

Before the trade, the Angels rotation consisted of Jered Weaver, C.J. Wilson, Dan Haren, Ervin Santana, and Garrett Richards, with Jerome Williams serving as a sixth starter and insurance for the first five. Greinke’s acquisition pushed Richards to the bullpen for this week’s series against the Rangers, but if Santana has another disaster start, he could be the one losing his job. Neither Richards or Santana have pitched particularly well this year, so replacing either with Greinke is a legitimate upgrade.

But, to be honest, the Angels could have already replaced either Santana or Richards if they didn’t perform all that well down the stretch. While Jerome Williams required a DL trip with “breathing issues” that he related to asthma and anxiety, he’s pitched pretty well since returning and has been a pretty effective starter for the Angels over the last year. Dating back to the beginning of August last year, Williams has thrown 145 innings with a 4.29 ERA/4.23 FIP/4.06 xFIP, a perfectly acceptable performance from a back-end starter. He doesn’t do anything amazingly well, but he’s solid across the board, and the Angels simply could have used him to replace Santana or Richards if they felt that was necessary.

Of course, Williams could have only replaced either Santana or Richards, so Greinke is still taking the place of the other, which means that they will have a much better pitcher on the hill once every five days than if they had stood pat. Using the ZIPS rest-of-season projections, we see that Greinke’s expected ERA over the final two months of the season is 3.28, while Santana comes in at 4.83 and Richards at 5.79. Even adjusting that for the move to the American League, a 1.0 to 1.5 run gap on a per-nine-inning basis can really add up, even over a period as short as two months.

Greinke will likely make 12 starts for the Angels in August and September, and he averages about six innings per start, so you can pencil him for around 70-75 innings going forward. At a 3.50 or so ERA level, he’d allow 27-29 runs in those innings. If we assume that the Santana/Richards hybrid would combine for a 5.00 ERA, that would equal 39-42 runs, so Greinke looks like about a +10 to +15 run improvement in the regular season. In other words, this move adds around a win to the Angels expected ledger, and if Greinke pitches really well, maybe even as many as two wins. That’s about as large of an upgrade as you expect to get at the deadline.

However, that’s the regular season. The Angels clearly acquired Greinke with the intention of playing in October and putting a devastating playoff rotation together that could carry them deep into the playoffs. With Weaver, Wilson, Haren, and Greinke, the Angels certainly have the best rotation of any AL contender, and perhaps the best rotation of any club fighting for a postseason berth in either league. Here, though, is where the significance of this upgrade seems to be diminished.

In the best-of-five Division series, only the Game One starter is asked to take the ball twice, and even in the best-of-seven League Championship Series and World Series, the team’s #4 starter only makes one start no matter how long the series goes. In fact, a #4 starter in the playoffs is effectively marginalized by the schedule to the point that it’s one of the least important positions on a playoff roster. And this is the position that Greinke effectively upgrades in October.

This acquisition essentially pushes Dan Haren into that #4 spot, meaning he’ll get just one start in each playoff series, while Weaver/Wilson/Greinke will be lined up to potentially make two starts each if the LCS/WS go seven games. But, while Greinke’s a good pitcher, the upgrade over Haren is much smaller than the upgrade over Santana/Richards. In fact, due to the playoff schedule, the impact of the #4 starter is fairly heavily marginalized. While Haren has struggled this year, pushing him into a lesser role for October isn’t nearly as impactful as pushing a poor player off the roster entirely.

While Greinke is likely to help the Angels make a push for the AL West, they probably could have gotten by in October with either Williams or a lower cost trade acquisition (such as Paul Maholm) in the #4 spot. Given who they already had in the rotation, the Angels probably needed Greinke less than just about any other contender.

That doesn’t mean this deal wasn’t worth doing, however. They still gain significant value from their increased odds of winning the division, especially since they also kept him from going to Texas by acquiring him themselves. And, reports suggest that Greinke had Anaheim high on his list of potential suitors, so they may end up getting him signed before he even gets to free agency, and perhaps at a price that helps justify the price they paid to acquire him. Given the Angels situation, trading future talent for present talent makes sense, and this was probably a good deal for the franchise as a whole. However, given that they already had three pretty good starting pitchers, I don’t know that this deal is going to do that much to improve their chances of going deep in the playoffs.