In my opinion, the Toronto Blue Jays have been one of the more surprising teams in all of Major League Baseball so far this season. Missing the Postseason with a 74-88 record last season, there was a distinct possibility that the Vladimir Guerrero Jr. and Bo Bichette era in Toronto would soon be coming to an end. Instead, Toronto signed Guerrero Jr. to a 15-year extension, made a couple of significant transactions to acquire players such as Andrés Giménez and Max Scherzer, and has ridden resurgent campaigns from Bo Bichette and George Springer to a 77-56 record so far this season, currently sitting atop the American League East.
At the trade deadline, the Blue Jays made a notable move to strengthen their starting rotation, acquiring Shane Bieber from the Cleveland Guardians in exchange for right-handed pitching prospect Khal Stephen. After undergoing Tommy John surgery at the beginning of the 2024 season, acquiring potentially two months of Bieber in exchange for six years of team control of a high-floor prospect like Stephen seemed like a risky proposition for Toronto, however, Bieber impressed in his first start as a Blue Jay, providing optimism that the acquistion of Bieber could be the missing piece to solidify Toronto’s starting rotation for this Postseason. This article will take a look at Bieber’s arsenal, examine the changes he has made since his last full season in 2023, and attempt to predict how well he will perform down the stretch and into the Postseason.
In the three seasons preceding his UCL injury, Bieber was an integral part of the Cleveland Guardians‘ starting rotation, particularly during the 2021 and 2022 seasons. Bieber’s best season as a member of the Guardians rotation arguably came in the 2022 season, when he produced a 25.0% strikeout rate, 4.6% walk rate, 2.88 ERA, and 4.8 fWAR over 200 innings pitched in 31 starts. While Bieber’s long-standing ability to command the baseball allowed him to pitch effectively, Bieber’s production declined notably in 2023, producing a 20.1% strikeout rate, 6.4% walk rate, 3.80 ERA, and 2.1 fWAR over 128 innings pitched in 21 starts. Bieber had a dominant two starts to begin the 2024 season, posting a 44.4% strikeout rate in a very small sample size of 12.0 innings pitched, before tearing his UCL and missing the remainder of the season. In his first start as a member of the Toronto Blue Jays on August 22nd against the Miami Marlins, Bieber pitched 6 innings, striking out 9 while allowing no walks and 1 earned run.
As shown by the table above, Bieber’s arsenal predominantly consists of five pitches: a four-seam fastball, a slider, a curveball, a cutter, and a changeup. In his first start in the 2025 season, Bieber used all five pitches to both right and left-handed hitters, particularly increasing his changeup and cutter usage to left-handed hitters, as these pitches’ movement profiles perform better against opposite-handed hitters (cutters move away from the “sweet spot” of the bat to generate sub-optimal contact, while changeups look similar to four-seamers out-of-hand, generating swing-and-miss). As mentioned earlier, Bieber has relied on his above-average command to allow his pitches to perform effectively throughout his career, and although one start is too small a sample size for location models to become reliable, FanGraphs’ Location+ graded all of his pitches as possessing above-average locations in his first start of the season.
Bieber has had to rely on his ability to command the baseball throughout his career because pitch quality models, which evaluate pitches solely based on their velocity, movement, and spin characteristics, have not been particularly fond of Bieber’s arsenal throughout his Major League career. As shown by the table above, pitch quality models such as Stuff+, StuffBot, and aStuff+ each graded Bieber’s “stuff quality” as below-average in 2023, with his arsenal producing a 91 Stuff+, 46 StuffBot, and 99 aStuff+. These three pitch quality models generally agree that Bieber’s “stuff quality” has improved so far this season, and since “stuff” models become reliable in small sample sizes, it provides a signal that Bieber has made a significant change to the quality of his arsenal.
The pitch that has improved the most in Bieber’s arsenal has been his changeup, with the offering possessing roughly 5 inches more vertical drop than it possessed when he last utilized the pitch in 2024. In 2024, Bieber’s changeup graded as a 79 Stuff+, 50 StuffBot, and 81 aStuff+, while so far this season, the pitch has improved to a 115 Stuff+, 80 StuffBot, and 111 aStuff+. This change in movement profile is due to Bieber adopting a “kick change”, a type of changeup that places a larger focus on generating vertical drop than arm-side movement. Popularized by Leif Strom at Tread Athletics, the kick change utilizes a spiked grip, allowing for the middle finger to “kick” the pitch’s spin axis, generating more vertical drop than a typical changeup. As a pitcher who has displayed supination tendencies (particularly the ability to throw a curveball at above-average velocity), Bieber was an ideal candidate to add a kick changeup this season, as the pitch does not require the same amount of pronation that a traditional changeup grip necessitates. While some of the pitch’s effectiveness can be attributed to the possibility that the Marlins were not anticipating this new changeup shape, the new changeup shape generated a 66.7% whiff rate in his first start of the season, providing optimism that the pitch will be a valuable addition to Bieber’s arsenal, particularly to utilize against left-handed hitters.
Another notable development of Bieber’s return to the Major League level was the resurgence of his four-seam fastball velocity. As shown by the table above, Bieber’s average four-seam fastball velocity was 92.7 MPH in 2021, before declining to 91.3 MPH in 2022 and 2023. After sitting at 92 MPH with his four-seam during his short 2024 season, Bieber has regained all of his fastball velocity in his first start of 2025, displaying an average four-seam velocity of 92.7 MPH in his last start. While my initial assumption was that perhaps Bieber experienced a velocity increase due to season debut-related adrenaline effects, it appears that Bieber also demonstrated this level of fastball velocity during his Minor League rehab stint, indicating that he can sustain this level of velocity over a sustained period of time. Each of the three “stuff” models gives his four-seamer an increased grade this season due to this resurgence in average velocity, and this improved pitch quality should allow the offering to be more effective moving forward. The revamped changeup shape and resurgence in fastball velocity have been encouraging indicators that Bieber is back as an impact starting pitcher and, while one start is still a very small sample size, could be a sign that the Toronto Blue Jays have solidified their starting rotation for a Postseason run. These adjustments have improved his fastball and changeup’s ability to generate swing-and-miss, making it likely that he will eclipse the 24.3% whiff rate he generated in 2023 over the remainder of the season.
Projection systems vary on how to prognosticate Bieber’s rest-of-season production. Steamer forecasts a 3.63 ERA with an 18.0% K-BB, ZiPS DC is even more optimistic at a 3.42 ERA, while OOPSY projects him for a 3.70 ERA, and THE BAT comes in more cautiously at 3.92. While command ability can vary from start to start, leaving Bieber vulnerable to a bad outing or two, the changes to the arsenal are promising enough that I am willing to place my bets his ERA will settle between the 3.42 to 3.63 range over the remainder of the season.
These projections don’t just matter for Toronto’s Postseason aspirations; they could also shape Bieber’s market value heading into 2026. Bieber currently possesses a $16M player option for the 2026 season, and his performance over his final five starts of the season will go a long way to determining whether he accepts the player option or enters free agency. Given how organizations are always in demand for more starting pitching depth, it appears that Bieber will likely elect to enter free agency after the season and secure a multi-year deal.
In conclusion, I am quite optimistic about Shane Bieber’s rest of season outlook. Bieber has a tough matchup in his next start, facing the Milwaukee Brewers on Friday, August 29th; however, it appears that the reinvented changeup profile and renewed fastball velocity are sustainable changes to his arsenal, which should allow him to be a valuable member of the Toronto Blue Jays starting rotation heading into the Postseason. Trading a high-floor, Top 100 starting pitching prospect for a potential two-month rental in Shane Bieber is, by definition, a risky move, but if Shane Bieber is truly back, the Blue Jays might have found their missing piece to a deep Postseason run.
Statistics as of the end of play on August 27th, 2025.
Photos by Icon Sports Wire and Wikimedia Commons | By Carlos Leano
