The 10 worst MLB players in August

The dog days of summer are officially over and we’re in the home stretch, you guys. Both the non-waiver and waiver trade deadlines are now in the past, meaning clubs have just one final month to show whether they’re worthy of a postseason berth.

After spotlighting the best hitters and starting pitchers from August, we’re doing the same for those guys on the opposite end of the spectrum. Once again, we’re going to rank hitter performances by wRC+, while Skill-Interactive ERA (SIERA) will be used for the starting pitchers.

It’s safe to say that these 10 players are happy the calendar has flipped to September.

August’s Five Worst Starting Pitchers

It seems like pitchers are always evaluated by the same traditional metrics, such as win-loss record, ERA, WHIP, strikeouts per nine innings and walks allowed per nine innings. This is exactly why we’re going against the grain and evaluating pitcher performance by SIERA.

SIERA attempts to measure the underlying skill of a hurler, but unlike FIP and xFIP, it doesn’t ignore balls put in play, and also attempts to give a more accurate picture as to why certain pitchers are better than others. A good SIERA is just like a good ERA — the lower the better.

Here are the five hurlers who struggled the most in August.

Like most things for the 2018 Baltimore Orioles, things just haven’t worked out since signing Andrew Cashner. Similar to last year, he’s struggled with his strikeout-to-walk ratio, and he hasn’t controlled the contact of opposing hitters nearly as much. The righty’s ground-ball rate has sunk down to 41.5%, which is not only seven percentage points lower than 2017, but it’s also on track to easily be a new career-low mark.

Ryan Borucki struggled in August when looking at his peripherals, but he’s one of two hurlers in the above table to nab three victories. Baseball, man. The southpaw has liked pitching at Kaufman Stadium, but may want to skip the road trips. He owns a 2.59 ERA and .305 wOBA allowed at home, but 6.40 ERA and .367 wOBA allowed as a visitor.

While Carlos Rodon has been on a roll lately, his peripherals tell us regression could hit at some point. His walk rate has increased each of the last three months, while his BABIP allowed has decreased and his strand rate has stayed abnormally high compared to the rest of his career. He is controlling the quality of contact, though, as hitters own a 17.6% soft-hit rate and 27.3% hard-hit rate against the lefty.

Edwin Jackson also had a great month while playing for the millionth team of his career (kind of), and the Oakland Athletics are likely hoping to ride him outperforming his peripherals all the way to October. His 4.87 SIERA for the year isn’t much different than 2017 (5.03), but his actual ERA sure is (5.21 in ’17, 3.03 in ’18).

The Milwaukee Brewers finally got the starting pitcher they desperately need for the stretch run, but they’re also hoping Gio Gonzalez can get back on track. That 7.47 August ERA was the worst among qualified starters, and he just hasn’t been the same since a strong start. After posting a 2.10 ERA through his first 64.1 innings this year, that number has shot up to 6.53 over his last 81.1 frames.