The Angels made a trade, and this analyzes it.
Today, the Angles acquired Tyler Skaggs and Hector Santiago while relinquishing Mark Trumbo to the Diamondbacks, along with at least one prospect. The White Sox (who sent over Santiago) will acquire Adam Eaton, a center fielder for (formerly) the Diamondbacks.
Frankly, the Angels made out quite well. But how well they made out depends almost entirely on how high you are on Tyler Skaggs. Skaggs has a wicked curveball and solid change to go along with two fastballs (89/90 mph). However, despite his solid stuff, in both of his major league stints (stretching two years), he has been destroyed, never posting an FIP below 4.8 or an ERA below 5. His xFIP, however, was significantly better, as he posted a 3.95 last year. (xFIP is basically FIP adjusted by park and with a normalized home run rate. Ideally, it sets the bar equal for a pitcher in Seattle and Denver. Some pitchers never outperform their xFIP, since their stuff isn’t good enough to avoid home runs at the major league level.) Whether or not Skaggs can avoid the four-bagger has yet to be seen. After all, his ground rate is well below average across the board. It goes without saying that ground balls are never home runs. Pitcher with high ground ball rates typically don’t have high home run rates, given that they have adequate demand. This decidedly was not the case for Tyler Skaggs this year.
Fastball velocity is inversely correlated with home run rates, and in the former, Skaggs isn’t great either. The average fastball velocity across major league baseball (for starters) is 91.4 mph. so when I said Skaggs’ fastball was average, at least in terms of velocity, it isn’t– it’s actually below by about 2 miles per hour. (Important to note: this isn’t completely extraordinary, since lefties tend to have a lower average velocity. This makes pitchers Aroldis Chapman that much more unique.) This, combined with not-exceptional movement (though, ironically, his four seam fastball does show above average sink), makes him more prone to fly balls, and fly balls are more likely (obviously) to be home runs than ground balls. Fly balls are also less likely to land for a hit, which is why his exceptionally high batting average (.308) and wRC+ (201, which is not good) against his four-seam fastball are a bit odd. His two-seamer is a bit better in that regard (.294/145), but even then it really isn’t a great pitch (at least using batted ball metrics). Batted ball metrics will fluctuate game-by-game and season-by-season, but the fact that he’s been rocked for two straight years is a bit concerning. Considering the fact that he really doesn’t have much velocity to play around with, he may always post above average home-run rates. Whether his fastball still allows lots of contact will fluctuate on the season, but he will probably improve in that regard with age.
One last concern: his fastball may be pounded because he has rather poor extension on the ball. Behind a pay wall, Doug Thorburn (writing for Baseball Prospectus in a pay-walled column) gives Skaggs literally the minimum grade for extension. Extension matters since it makes ever pitch relatively faster. In other words, a 90 mph pitch travels 132 feet per second, or .416 per 55 feet (roughly the distance from the pitcher’s hand to the plate.) If that 55 feet can be reduced by just two feet, the pitch arrives in .4015 seconds, or roughly the same time as a fastball 3 mph faster from 55 feet. Those two feet makes the 90 mph pitch (to the batter) look like a 93 mph pitch, which is a huge jump. (*Note: feel free to check my math. It could very well be wrong. But release distance does play a role in relative velocity.) In this regard, according to Thorburn, Skaggs is awful. This could make his already-mediocre fastball seem even slower, which could explain the home run issues. If this is the case, hitters will probably hit Skaggs’ fastball well for the majority of his career assuming nothing changes.
These are all of his faults. He does have other positive qualities. His curveball is truly excellent, and part of the reason for his struggles were due to a lack of fastball command. If he gets that sorted out, his fastball will begin to play better in games, though it may never be a particularly great pitch. Assuming he does, he should be a solid #3 option.
On the Hector Santiago front, I confess I know little. What I do know is that his peripherals point to a decline next season. Steamer projects a 4.64 ERA in 144 innings. In other words, a fifth starter. Santiago has an above average fly ball rate and the Angels have Mike Trout and Peter Bourjous, so his ERA may be a bit lower (I don’t know if Steamer adjusted for his team or not.) Using no math whatsoever, I’m going to project a 4.3. He may very well beat it.
How This Impacts the Rangers
The Angels did quite well in the trade, though how much a (to this point) home run-challenged pitcher will succeed in Arlington has yet to be seen. Still, this should make the AL West race a bit tighter, though the A’s and Rangers should still battle for first, with Anaheim and Seattle duking it out for third. The Angels are the favorite for third, and could make things interesting. But unless Albert Pujols comes alive this season in a big way (doubtful) and Josh Hamilton bounces back (more likely) the Angels will still be an expensive flop and the Rangers still a division-crown contender.