Rumors of his demise were premature. After Mat Latos was traded to the Cincinnati Reds exactly one year ago, many felt that his fantasy value would tumble. Moving from the friendliest pitcher’s park to a home field that inflated offense would not be a good change. When you also factor in a fly ball rate that has always been higher than the league average and the significant difference in home run factors between the two parks, it really wasn’t much of a surprise that fantasy owners were concerned. But, to hell with park factors said Latos, as he posted an identical ERA this season as last year with San Diego. He even posted a better ERA at the Great American Ballpark than in away parks.
Now having said that, deeper digging yields some more interesting tidbits. He managed to post a better home ERA despite a large decline in strikeout rate, a higher percentage of fly balls and a higher rate of those fly balls leaving the yard. So, the magic was really just due to a .247 BABIP at home and a LOB% over 80%. The ballpark did hurt him turning more fly balls into home runs, but luck in other aspects of his game more than offset it. This is what happens over small sample sizes.
Overall, his skills did decline from his San Diego days as his SIERA jumped, even though his ERA and WHIP barely budged. A .266 BABIP could be thanked for that and that’s unlikely to happen again. His strikeout rate has actually fallen for two straight seasons, though the rebound in ground ball rate was nice to see, and necessary given his new home. But although the strikeout rate has dropped, his SwStk% has remained relatively stable (the two-year decline is minimal) and it sits at a level that suggests a much better rate than 8.0. So, in other words, all else equal, Latos should enjoy a strikeout rate rebound next season.
Latos opened the month of April in poor fashion and those that expected a down year were looking smart. He struck out just 18 batters in 28.2 innings, he was allowing hits all over, not stranding runners, and before long, his ERA stood at 5.97. Then the more familiar Latos reappeared when the calendar flipped to May. He struck out 11 Pirates batters over 6.0 innings, and aside from a 4.19 June ERA (oddly, xFIP tells us it was actually his best month), he never posted a monthly ERA above 3.34.
In April, Latos threw his change-up about 11% of the time. As Ben Duronio noted back in September, he then essentially ditched the pitch for the rest of the season, throwing it just about 3% of the time. The whiff rate on the pitch was relatively low, so he scrapped it and increased the usage of his slider pretty significantly and also threw his curve-ball more often. He threw his slider for strikes more frequently and his whiff rate increased even further on what was already clearly his best pitch.
Although I am rarely a fan of doing this, I actually would suggest completely throwing out the first month of his season as he was clearly a different pitcher from then on. After doing this, his strikeout rate jumps to 8.3, his walk rate drops slightly, and his ground ball rate increases. Since he was a bit lucky over the season given the ERA/SIERA discrepancy (a SIERA which also assumes the HR/FB rate will regress, and that may not), those skill changes over the final five months are enough to offset that good fortune. That means that instead of expecting Latos’ ERA to rise next season, it should again be similar.