One of the key causes of the White Sox’s awful April play was their horrendous bullpen. Flash forward 35 days, and suddenly the script has flipped. Since the start of May, Chicago is a respectable 19-14, and the relievers are a huge part of the turnaround. Whether that trend will continue remains to be seen, but the 180-degree switch is worth analyzing regardless.
Months are relatively small sample sizes in the grand scheme of a full baseball season, but the stark contrast between April and May for the Sox bullpen is truly astonishing. After the first month of the season, the South Siders sported MLB’s worst bullpen ERA at 6.86, worse than even the lowly Oakland Athletics. Since then, though, the White Sox sit in fifth place with a 2.96 ERA.
Take a look at the player-by-player breakdown:
| Player | April ERA | May/June ERA | April FIP | May/June FIP |
| Kendall Graveman | 3.72 | 0.00 | 6.39 | 2.68 |
| Keynan Middleton | 3.86 | 0.00 | 2.72 | 2.16 |
| Reynaldo Lopez | 8.74 | 1.98 | 6.02 | 3.72 |
| Gregory Santos | 1.88 | 2.35 | 2.52 | 3.15 |
| Joe Kelly | 7.71 | 2.77 | 3.72 | 1.90 |
| Jimmy Lambert | 6.92 | 4.32 | 6.44 | 7.01 |
| Aaron Bummer | 9.64 | 5.79 | 3.93 | 2.10 |
Outside of Gregory Santos, every single pitcher saw their ERA fall drastically between April and May/June totals. The story was virtually the same for FIP, showcasing that the rebound was no joke. Seriously, going an entire month where only one of your relief arms records a FIP over 3.75 is impressive.
If that doesn’t tell the full story, let’s look at May/June from an outings perspective:
| Player | Scoreless outings | Total outings |
| Keynan Middleton | 13 | 13 |
| Kendall Graveman | 13 | 13 |
| Reynaldo Lopez | 11 | 14 |
| Joe Kelly | 10 | 12 |
| Gregory Santos | 10 | 13 |
| Aaron Bummer | 9 | 11 |
| Jimmy Lambert | 6 | 9 |
Add that all up, and you get 72 scoreless outings out of 85 chances, for a success rate of 84.7%. At the end of April, that number was hovering around 60%. Middleton and Graveman have been especially lights out, combining for a remarkable 26.2 innings of scoreless baseball for the South Siders.
The nitty gritty
What were the primary factors in such a stark turnaround? There are a few big ones.
First, Keynan Middleton basically replaced Jake Diekman towards the end of April. While Diekman was struggling mightily, Middleton has been nothing but lights out since the jump. Hahn and Co. cutting their losses on the veteran lefty seems to have paid off.
Second, Reynaldo Lopez completely flipped the script on his contact profile. In April, Lopez was allowing a 55.2% hard-hit rate but shaved a full 40 points off to a mere 15.2% in May/June showings. That tracked with four home runs yielded in April, as opposed to just one bomb surrendered in May/June.
Then there was Joe Kelly activating God Mode. Since April ended, Kelly has walked just one batter while striking out 17 in 13 innings pitched. While his overall ERA is high, outlining his awful luck, his season FIP and xFIP are at an eye-popping 2.38 and 2.16 mark, respectively.
Lastly, Aaron Bummer found his command and more or less remembered how to pitch like we know he can. He finished April with an 8.68 K/9 and 6.75 BB/9, but after that has notched a 9.64 K/9 and 2.89 BB/9. Like Kelly, his overall year can be characterized as unlucky with a ridiculous 7.71 ERA on top of a 3.02 FIP and 4.12 xFIP.
What to watch for
Generally, it’s unlikely that the bullpen can continue with their current dominance, as the peripherals say there was some luck in May to go with a much tougher upcoming schedule.
Kendall Graveman seems most likely to endure a rough patch, as his scoreless outing streak has come alongside an absurdly low BABIP allowed. Middleton seems much more the real deal, but given his career arc, is this the real him? Gregory Santos is also surprisingly effective, but he’s been doing that all season. Whatever the case, the pen is clearly not one of the worst in baseball as April may have had you believe.
Player-wise, it seems probable that the injured Jimmy Lambert has lost claim to a major league roster spot with Garrett Crochet and Liam Hendriks back healthy. Those two players, meanwhile, have much to prove as they adjust to regular pacing with the White Sox. Crochet hasn’t been very good in his first six innings pitched, but that’s too small a sample size to assume much. Hendriks struggled in his first showing since recovering from cancer but has since looked stellar.
Given the mediocre state of the starting pitching, Pedro Grifol will need continued quality innings from his relief arms if his team wants to hang in the AL Central race through June.
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Featured Image: David Banks-USA TODAY Sports
Last season I wondered if our pitching coach could exceed without the Tony LaRussa meddling? Just maybe, he has. With that said, there are some hard facts about the current state of the White Sox.
1). There are 12 American League teams ahead of the ChiSox for a Wild Card berth. Though 3 1/2 months remain, twelve is insurmountable.
2). The White Sox are 47 runs from break even, in other words, only Oakland, Detroit and Kansas City are worse than our Sox. Excepting Colorado, 14 National League teams are more productive than our WSox.
It would appear the White Sox will need to win the division, but there are three teams higher in the standings. With roughly sixteen weeks of baseball left, time is on our side, but not so the predictability that Minnesota, Cleveland and Detroit will continue treading water. Closing the 5 1/2 game gap with one team with sixteen weeks is doable, but not with two other teams in the mix.