Tanner Bibee loves his fastball. His fastball does not love him back anymore.

Since his debut, Tanner Bibee’s fastball has been a below average offering by FanGraphs’ Stuff+. For those unfamiliar with stuff+, which only values the physical characteristics of a pitch (release point/velocity/movement). In his debut season, his fastball sat at a 90 stuff+. Last season, it peaked at 92. In 2025, Bibee’s fastball stuff+ has plummeted down to 85, becoming one of just 30 starting pitchers with a fastball stuff+ below 90. Of those 30 pitchers, Bibee’s 14% whiff rate ranks 23rd. Its usage rate is down to 26.6% this season after living comfortably in the 40% range in his first two seasons. Tanner Bibee is breaking up with his fastball, but like all breakups, letting go hasn’t been easy.

Despite Bibee’s usage dropping significantly, he continues to turn back to the ex in the absolute worst of times despite finding newer, better friends this season that lift him up rather than drag him down.

Tanner Bibee has found a healthy relationship with his cutter, and the two of them together have blossomed. Of the 78 starting pitchers with at least 60 innings pitched who have thrown a cutter, Bibee’s 102 stuff+ ranks 13th. Similar to the fastball, Bibee has cut the cutter usage down from 25.8% last season to 19.5% in 2025. That’s because a new friend has entered the group: the sinker. Bibee has thrown the sinker a lot more lately. Since the start of July, Bibee’s sinker usage has gone from 15.7% up to 21%, just 2.5% less than his fastball. On the season overall, Bibee’s sinker has notched a 112 stuff+ grade, and even with its usage increase, it’s still at 110 since the start of July. Among 89 starting pitchers with at least 100 innings pitched this season, Bibee is one of just five with a 100 grade or better on both their cutter and sinker. The others are Drew Rasmussen, Hunter Brown, Max Fried, and Garrett Crochet. Of that group, Bibee’s whiff rate of 23.2% between the two pitches ranks second behind Crochet. In fact, of the 54 pitchers in baseball with at least 500 combined thrown sinkers and cutters, Bibee’s whiff rate ranks third behind the aforementioned Crochet and Kumar Rocker.

Everyone has the Summer fling with someone who totally isn’t your ex, but you have to tell everyone else that just so they know. For Tanner Bibee that’s the sweeper. Bibee and his sweeper are seeing each other more, and the closer they get, the better their relationship grows in many aspects. His sweeper is running a 113 stuff+ grade, tied with his always constant changeup for his best pitch by stuff+. A season ago, Bibee used a sweeper just 6.5% of the time. The two really hit it off last June, seeing a 15% usage spike, but for whatever reason, they kind of just went their separate ways for a while despite its returns being incredibly promising. It wasn’t until the 2025 season that the sweeper has come back and become a permanent fixture in Bibee’s arsenal. Once again, the returns have been terrific on it, almost. Opponents are hitting just .176 against the sweeper with a .252 xwOBA and a 31.6% whiff rate. Bibee’s sweeper usage against lefties in particular has seen great effect, as lefties whiff 32.3% of the time against the sweeper, a top 10 mark in baseball among right-handed starting pitchers.

You’re seeing how effective all of Bibee’s other offerings have been, so why can’t he quit the fastball? Despite the quality of Bibee’s sweeper, it effectively has become just like his fastball in 2-strike counts. He can’t generate swings out of the zone with it, and this has resulted in Bibee’s sweeper being a bottom-10 sweeper in terms of put away rate (2-strike pitches that result in a strikeout) at just 18.4%. His fastball is also bottom-10 heater by put away%. Of slider-type pitches (slider, sweeper, slurve), Bibee’s 26.1% chase rate is 5% less than MLB’s average chase rate on those offerings, and it only gets steeper in 2-strike counts. The MLB average chase rate in 2-strike counts against slider-type offerings is 39%. Bibee’s chase rate in those scenarios is 29.9%. It’s not like he isn’t trying for the whiffs either. Bibee’s 64.8% out-of-zone sweeper rate in 0-2, 1-2, and 2-2 counts is just 0.2% higher than MLB average. Suddenly, the 24th percentile chase rate overall begins to make sense.

Bibee has been abysmal with two strikes this season, and it’s simply because he doesn’t know what to turn to. All too often, he feels as if he’s left no choice other than to turn back to that dreadful ex of a 4-seamer solely because they have history. In 2023 and 2024, Bibee was getting whiff rates on his fastball at 25.2% and 22.5% respectively in 0-2, 1-2, and 2-2 counts. In 2025, that rate has plummeted all the way down to a paltry 6.3%, the worst mark in baseball.

In spite of this, opponents are only hitting .158 off Bibee’s fastball in those counts, so clearly it’s working, right? Somewhat. Bibee’s 2-strike fastball has an average exit velocity of 93.5 mph and a hard hit rate of 45%. He’s one of 12 pitchers to surrender 93 mph or higher average exit velos and at least 45% hard hit rates to his fastball. His .260 wOBA against is 145 points lower than the .405 xwOBA. On the season, he’s outperformed his fastball’s expected 2-strike data significantly, but it’s catching up to him in a hurry.

I first noticed how bad Bibee’s 2-strike struggles were becoming on his June 26th start against Toronto. Jonatan Clase was up with no outs to start the inning, and a bad changeup was left in the top of the zone, and Clase blooped it into centerfield for a leadoff base hit. The location was awful, but it’s a fluky base hit, no worries. Next thing you know, the bases are loaded, and there’s just one out. Nathan Lukes is up for the Jays. Bibee gets ahead of Lukes 0-2 with relative ease, and then it falls apart. Bibee goes to a fastball up trying to get a chase. He misses the zone by a foot. He goes to a changeup low, misses the target by six inches. Now it’s 2-2 after two noncompetitive pitches. Bibee turns to his sweeper and misses the outside edge by two feet. Never let anyone tell you these are good at-bats by the hitter. All he had to do was watch as Bibee turned an 0-2 count with a chance to get out of a jam into a 3-2 count completely by his own doing. Bibee’s next 3-2 offering was a much better pitch, a sinker bearing down and away, but Lukes fouled it off. Then Bibee makes his biggest mistake, hanging a room service sweeper right down the middle, and Lukes rifled it into right field for a 2-RBI single.

Since this start, Bibee’s 2-strike fastball is getting demolished. His heater is surrendering a .364 average against with a .447 xwOBA and 97.6 average exit velocity on 8 balls in play including a home run. This has resulted in a 63% hard hit rate with a low 8.7% whiff rate while his sweeper and changeup are both running sub .230 averages against with xwOBA marks each under .300 and whiff rates of at least 37% each. It’s simply a habit he has to break. He’s turning to his fastball 19.5% of the time in 2-strike counts since June 26, and he’s tallied more than five strikeouts in a start just three times over that span and has failed to go at least five innings three times as well. You can only bang your head against a wall so many times before you realize you’re going to bleed a lot more often than the wall will.

Is the solution to completely scrap the heater? No, mostly because it’s illogical to think that Bibee would be willing to do that, but he needs to throw it even less than he already is. It’s been a bread and butter pitch for him for too long for him to quit, but it’s quite literally the primary reason he can’t seem to find success in 2025. So, what are the alternatives? He needs to trust his sinker in these spots. The movement profile is great from his high arm angle. We mentioned just how rough the fastball has been at putting hitters away (10.2% put away rate), but his sinker has fared a lot better in 2-strike spots by more than double, it’s just all about location. Bibee’s sinker sits at 8th in put away rate among pitchers with 100+ PA against at 23.8%. Simply put, it’s time to let go, move on, and let something better lead Bibee the rest of the season. The overall expected numbers do not indicate a pitcher with a 4.60 ERA, but batters aren’t going to just get out for him, he has to finish counts. I look forward to the rest of Bibee’s season and seeing if he can escape his ex once and for all.