Loudly and quietly, the Blue Jays made a series of improvements around deadline time. Very conspicuously, they added an incredible shortstop. Very conspicuously, they added an incredible starting pitcher. Somewhat conspicuously, they added a decent left fielder. It was the bullpen work that went almost unnoticed. Armed with some new personnel, and with some shifted personnel, the Jays came away from July with a stronger relief unit. Really, they came away with a stronger everything, and the team has taken off, but the bullpen, now, seems like it’s become a strength. It’s just not what drew the headlines.

The Rangers aren’t the Blue Jays, but they are in the race, and there are a few parallels here. Something in the vicinity of a .500 team around deadline time. A huge impact addition, in the form of Cole Hamels. And a very quietly strengthened bullpen, that’s given the Rangers some late-inning reliability for maybe the first time all year. Let’s face it — the second wild card isn’t going to a great team. The Rangers aren’t a great team. They’re becoming a solid team, however. A team that might as well deserve to keep playing. It was an awful big August, and it was a month made possible by improvement in a bullpen no one was paying attention to.

I can’t remember the last time I used Win Probability Added (WPA) on the front page of FanGraphs. It’s of limited analytical use, because it’s of limited predictive use, and we’re usually in part trying to tell the future. But I do like the ability to tell a story, so I want to quickly tell you the story of the 2015 Texas Rangers. This table shows WPA by month, split by lineup, rotation, and bullpen. Highlighted is the strongest unit of each month. The stat is imperfect, but it can convey an idea.

2015 Rangers Component WPA Month Lineup Rotation Bullpen April -2.4 -1.2 0.1 May 3.9 -0.4 0.5 June -0.8 1.5 -0.3 July 0.6 -2.2 -0.4 August 1.2 0.9 2.4

The bullpen made the biggest positive difference in April, but it was a bad April — the Rangers lost twice as often as they won. May was better, and the Rangers in May were most carried by their offense. In June, the rotation took over, and then in July, it was back to the lineup again. Now look at the last row. It’s solid everywhere. August was good. But the bullpen was huge. Going into the All-Star break, the Rangers bullpen ranked 21st in WPA, and even worse than that in the more familiar metrics. By WPA, the bullpen in August ranked second. It posted a season-best ERA, a season-best FIP, a season-best xFIP, and a season-best strikeout rate. Just by the nature of things, bullpen success can run out almost overnight, but the Rangers finally have a bullpen they don’t have to fear giving the ball to. Shawn Tolleson and Keone Kela — those guys were already around. But Sam Dyson and Jake Diekman have proved to be critical additions. You’re forgiven if you didn’t think much about them before.

Earlier in the year, Jeff Banister remarked that his bullpen didn’t exactly have set roles. That was then, but things have evolved. The unit’s gotten better, and now there’s essentially a big four, consisting of Tolleson — Kela — Dyson — Diekman. In August, those four threw just over 50 innings. They posted a 1.57 ERA, with a 2.54 FIP and a groundball rate over 60%. Those four, together, had a WPA of almost 3. This is the core of the good version of the bullpen, and it’s nothing you would’ve given a second thought to a few months ago. There’s not any name value. There’s not a lot of history. They’re all earning more or less the league minimum.

Diekman was thrown into the Hamels trade. That might not be a fair way to put it, since he has a big arm and the Rangers must’ve wanted him for a reason, but when that trade went down, Diekman was probably talked about the least. He was sitting on an ERA over 5. That’s not as interesting as an ace or a set of prospects. Speaking of uninteresting, Dyson was picked up at the deadline and for most it probably never registered. Dyson came from the Marlins for players you likely haven’t heard of. He was a middle-relief addition to a team three games below .500. These are the moves you swat out of the way so you can focus on the bigger deadline moves and rumors. The fun stuff.

The fun stuff included the Rangers getting Hamels. A month in, Hamels has done less than Diekman and Dyson. That doesn’t mean Hamels is some sort of liability. You just can’t know who’ll make a difference in a month of baseball.

With both new relievers, there’s evidence of a plan. Diekman has a big fastball. Doesn’t always control it, but he has even less control of his other stuff. With the Rangers, so far, he’s thrown more strikes, cutting his walk rate in half. He’s thrown more fastballs, at the expense of sliders and changeups. It’s improved his zone rate. You can break it down further. Diekman isn’t doing too much different against lefties. Against righties, he’s gone from 72% fastballs to 86%. The Rangers want Diekman to trust his heater, and the results to this point are promising.

The change with Dyson is even bigger. Dyson’s a sinker-baller, hovering around the mid-90s. With the Marlins, he threw 70% sinkers. With the Rangers, he’s thrown 88%, and that’s how you get a bunch of strikes, with one walk out of 59 batters. More remarkable, Dyson with Texas has yielded 46 balls in play, and 37 of those have been grounders. Dyson is a strike-throwing groundball machine, which helps him to work out of his and other jams. He doesn’t give up automatic contact, either, so you can’t dismiss the chance of a strikeout.

Diekman has helped. Dyson has helped. Kela is another pseudo-addition. He began on the roster, but he’s only improved. Through the All-Star break, he had 37 strikeouts and 12 walks, with a 95 mile-per-hour fastball. Since the break, he has 22 strikeouts and three walks, with a 97-mile-per-hour fastball. His other pitches are also up two ticks. Kela was recently demoted for a spell, the Rangers trying to do what they could to keep him fresh, but he’s been used heavily for a reason, and the second half has been entirely positive. The fringe prospect has turned into a crucial rookie for an unexpected contender.

Tolleson is the staple, the steady no-nonsense closer, and even he was a nobody waiver pick-up a couple Novembers ago. Before this year, he had zero career saves, and he didn’t have much experience in high-leverage situations. The Rangers got him to learn and improve a changeup, and now he can retire hitters on both sides. In the beginning, Neftali Feliz got the saves, both attempted and successful. He was a bust, and the Rangers haven’t missed him. They simply gave the ball to someone the Dodgers had given away for free.

A bullpen is always hard to predict, and that’s in part because a bullpen is always evolving. The Rangers’ bullpen has evolved, from a weakness into something that at least isn’t a liability, and that might be a strength. It’s happened at a good time for a team that used the month of August to assert itself in the race. Slowly, Shawn Tolleson proved himself an effective solution for the later innings. Keone Kela turned heads, and has gotten only stronger. Then the Rangers added both Sam Dyson and Jake Diekman, and with little adjustments their powerful arms have boosted a unit in bad need of depth. I don’t know if the Rangers are going to make the playoffs in the end. I do know I’m running out of reasons to think they won’t.