Adjustment Watch
Nolan McLean
The sweeper changed, McLean struggled afterward, and his recent rebound has strengthened with another dominant stretch — accompanied by broader pitch-mix and command changes, not a proven sweeper recovery.
The timing is meaningful, but the data does not prove the sweeper change caused the decline or that the later pitch-mix changes caused the rebound.
July 19 vs. Philadelphia — 6.0 scoreless innings, 2 hits, 2 walks, 10 strikeouts
The rebound strengthened with another dominant outing. Figures below come from refreshed Statcast and MLB Stats API data for this start.
| Pitch | Count | Usage | Velo | HB (in) | VB (in) | Zone | Whiff | Chase | CSW | RV/100 |
|---|---|---|---|---|---|---|---|---|---|---|
| sinker | 32 | 34.4% | 95.5 | -18.0 | 5.9 | 65.6% | 6.3% | 27.3% | 25.0% | +4.43 |
| four-seam fastball | 23 | 24.7% | 96.3 | -12.8 | 14.2 | 34.8% | 44.4% | 26.7% | 30.4% | +3.81 |
| curveball | 17 | 18.3% | 81.7 | 17.1 | -13.3 | 23.5% | 37.5% | 53.8% | 35.3% | +0.34 |
| sweeper | 6 | 6.5% | 86.7 | 14.2 | 2.1 | 16.7% | 50.0% | 40.0% | 33.3% | -3.13 |
| slider | 7 | 7.5% | 88.4 | 10.7 | 6.5 | 42.9% | 66.7% | 50.0% | 42.9% | +0.36 |
| cutter | 5 | 5.4% | 91.7 | -0.1 | 7.8 | 80.0% | 33.3% | 100.0% | 60.0% | +16.46 |
| changeup | 3 | 3.2% | 89.4 | -12.7 | -0.6 | 33.3% | 0.0% | 50.0% | 0.0% | +3.37 |
This start continued the recent pattern of more four-seamers and curveballs, fewer sweepers, and limited walks — with a heavy sinker day (34.4% sinker usage versus 31.5% across the latest five starts). By run value on a larger pitch sample, the sinker and four-seam were the strongest contributors; the sweeper remained negative. That describes what accompanied the outing. The evidence does not prove causation.
Trend classification from the public finding: initial decline recent rebound. The rebound is measured against the deterministic post-adjustment window excluding the latest five starts (9 starts), not by hand-picking a turnaround date.
McLean began the season missing bats, limiting walks, and preventing strong results across both traditional and underlying metrics.
After the sweeper changed shape, McLean’s strikeout advantage shrank, walks became more costly, and both his surface results and underlying performance worsened. This describes what happened afterward — not that the sweeper caused the stretch.
Latest three starts (July 5 through July 19; 2026-07-05, 2026-07-10, 2026-07-19): 1.00 ERA, 1.81 FIP, 23.6% K−BB.
Latest six starts (June 17 through July 19; 2026-06-17, 2026-06-24, 2026-06-30, 2026-07-05, 2026-07-10, 2026-07-19): 1.95 ERA, 2.47 FIP, 24.3% K−BB.
McLean’s recent performance looks much closer to his strong opening stretch, and the July 19 start extended that rebound. Underlying metrics — including FIP, K−BB rate, expected outcomes, CSW, walk rate, zone rate, and run value — support the turnaround, not ERA alone.
Run value estimates how many runs a pitcher prevented or allowed relative to average over 100 pitches. On this page, higher (more positive) run value favors the pitcher.
Comparing the 9-start post-adjustment struggle (May 2 through June 17) with the latest five starts (June 24 through July 19). The rebound coincided with these changes.
The rebound does not look like the sweeper returning to its old form. Recent performance was accompanied by more four-seamers and curveballs, fewer sweepers, better strike throwing, and fewer walks, with sinker and four-seam effectiveness also stronger in the recent window. The evidence does not prove causation.
McLean’s sweeper lost sideways movement and gained vertical movement around May 2.
He went from an excellent 6-start opening stretch to a 9-start post-adjustment window in which his ERA, FIP, strikeout-minus-walk rate, expected outcomes, and run value all worsened.
McLean rebounded over his latest five starts through July 19, including six scoreless innings and 10 strikeouts against Philadelphia. He has thrown more four-seamers and curveballs, fewer sweepers, more strikes, and fewer walks.
The sweeper adjustment is real, but his rebound appears connected to a broader approach change rather than an improved sweeper.
The sweeper clearly changed shape and continued changing afterward. But its recent run value remained poor, and its usage declined during McLean’s rebound.
Small-sample evidence: 21 before-period plate appearances; 29 after-period plate appearances. 16 before-period tracked balls in play; 38 after-period tracked balls in play.
These pitch-specific outcome samples are too small to conclude that the altered sweeper caused the decline. xwOBA here is a Statcast-style estimate, not confirmed as official Savant leaderboard xwOBA.
Before-and-after results describe what happened after the adjustment window. They do not prove that the pitch change caused the results.
Before period: 2026-03-29 to 2026-04-26. Full after period: 2026-05-02 to 2026-07-19. Struggle window: 2026-05-02 to 2026-06-17. Recent six: 2026-06-17 to 2026-07-19. Recent five: 2026-06-24 to 2026-07-19. Recent three: 2026-07-05 to 2026-07-19.
McLean’s season has not been a simple decline. He opened the year pitching at a high level, struggled after his sweeper changed shape, and has recently rebounded — with the rebound strengthening through July 19 — with a different pitch mix and better command. The sweeper remains worth monitoring, but the recent improvement looks broader than one pitch.
Full pre–May 2 versus full May 2–July 19 averages. Use the three-phase section above for the middle struggle and recent rebound.
| Stat | Before May 2 | May 2 onward |
|---|---|---|
| ERA | 2.55 | 3.69 |
| WHIP | 0.85 | 1.21 |
| Innings pitched | 35.1 | 78.0 |
| Strikeouts | 45 | 90 |
| Walks | 10 | 31 |
| Hits | 20 | 63 |
| Home runs | 2 | 8 |
| Opponent batting average | .161 | .220 |
| K/9 | 11.46 | 10.38 |
| BB/9 | 2.55 | 3.58 |
| Stat | Before May 2 | May 2 onward |
|---|---|---|
| K rate | 33.3% | 26.9% |
| BB rate | 7.4% | 9.3% |
| K minus BB rate | 25.9% | 17.7% |
| FIP | 2.21 | 3.77 |
| wOBA | .229 | .319 |
| Statcast-style xwOBA estimate | .241 | .304 |
| BABIP | .234 | .293 |
| Hard-hit rate | 18.0% | 21.4% |
| Barrel rate | 3.3% | 3.2% |
| CSW rate | 31.9% | 27.8% |
| Run value per 100 pitches | +1.68 | +0.08 |