On Thursday, I looked at American League starting pitchers who showed up on the last 30 day SIERA leaderboards that would be considered surprising. Today, I will cover the entire league, but look at the opposite end of the spectrum. These are the pitchers whose skills have really declined over the last 30 days. Is it the beginning of a trend or just small sample randomness over a long season? Let’s find out.
Matt Moore – 5.69 SIERA
For a while now, I have been touting Moore as a buy low opportunity. In June, he made me look good as he posted a 3.16 ERA, his first month below 4.00. But the wheels have fallen off in July, as he has completely lost his control, walking 13 batters in 16.2 innings and striking out just 9. His velocity has been fine and in two of his three starts, so has his F-Strike%, while his SwStk% remained strong in two of three as well. On the season, his SIERA is actually right in line with his ERA, so this is not a matter of him having bad luck. The bet here really comes down to assuming that his control improves as his advanced metrics suggest. If you’re an owner on the fringe of finishing in the money and want to take a risk, he should come cheap enough and provide an excellent risk/reward opportunity.
C.J. Wilson – 4.82
Due to continued outperformance of his expected ERA metrics, Wilson really seems to divide the crowd when it comes to projecting his future performance. Though his last 30 day ERA has jumped to 3.94, which is much more in line with his overall skill set, that is still nearly a full run below his SIERA. As I expected, Wilson couldn’t maintain last year’s control improvement or his strikeout rate gains. For a pitcher who throws a well below average percentage of first pitch strikes, it’s difficult to expect that walk rate to drop much over the rest of the way. His SwStk% is down from last year and even though his strikeout rate is down, it may even decline further. While Wilson may have some sort of HR/FB suppression skills, it is doubtful he can keep his BABIP as low as it currently sits, especially as a ground ball pitcher since those types of balls go for hits more frequently than fly balls do. Since he doesn’t induce a whole lot of pop-ups and has allowed a league average line drive rate, you have to wonder how he has managed to keep that BABIP so low. Since his season stats still look elite, he remains a prime sell high guy.
James McDonald – 4.68
Is the honeymoon over? I’ve been saying that McDonald’s poor F-Strike% suggests that his control gains are a mirage, and in July we might finally be seeing a version of him that is closer to what we’ll get the rest of the season. He has posted a walk rate of 5.3 during the month after two straight months at 2.1, while his strikeout rate has sat below 7.0 since the beginning of June. According to SIERA, his skills are still the best they have ever been, but his walk rate is still well below where I think it will end up. So, his SIERA may continue to hear North, while his ERA comes along for the ride. There is absolutely no reason to believe he can possibly sustain a .257 BABIP, especially given his 22% line drive rate and miniscule pop-up rate. The bottom line is that we have worsening skills along with a pitcher who has already been lucky to begin with, which all means that owners might want to scramble to trade McDonald away while his ERA remains below 3.00.