Research Report · March 2026
Seattle's Defensive Adaptation to LAR 13 Personnel: A Three-Game Study
Updated reframe of the original LAR 13 Personnel Usage report (February 2026). Covers Weeks 11, 16, and the NFC Championship. Data via nflreadpy / nflverse and PFF. · Read the full narrative →
The LA Rams deployed 13 personnel (1 RB, 3 TE, 1 WR) against Seattle at the highest rate of any opponent matchup in the 2025 season: 50.8% of plays across three games. Despite this, Seattle won the series 2–1 including the NFC Championship. The Seahawks countered by maintaining nickel/dime personnel at a league-leading rate, betting on defensive back versatility over personnel adjustments. EPA data shows the Rams' 13 personnel was roughly one-third as efficient against Seattle as it was league-wide.
Table 1 — Series Overview: LAR 13 Personnel vs. SEA
| Game | 13 Usage % | Result | 13 Efficiency | SEA Personnel |
|---|---|---|---|---|
| Week 11 (@ LAR) | 36.0% | LAR win | 2.7 yds/play | Nickel/Dime 88% |
| Week 16 (vs LAR) | 61.4% | SEA win (OT) | 5.9 yds/play | Nickel/Dime |
| NFC Champ (vs LAR) | ~55% | SEA win 31–27 | 8.1 yds/play | Nickel/Dime |
| AGGREGATE | 50.8% | SEA 2–1 | +0.076 EPA/play | League-high nickel rate |
Table 2 — League Context: LAR 13 Personnel
| Metric | vs. SEA | Season-Wide |
|---|---|---|
| EPA/play | +0.076 | +0.214 |
| Success rate | 42.4% | 52.3% |
| 13 usage rate | 50.8% | 30.8% (NFL #1) |
| 13 EPA rank (league-wide) | — | #2 (min 30 plays) |
Table 3 — SEA Defensive Personnel vs. LAR 13
Seattle maintained its nickel/dime base regardless of offensive personnel. Six defensive backs played 60%+ of snaps across the three matchups. PFF grades by game show who held up — and who didn't:
| Player | Season DEF | Season COV | Wk11 COV | Wk16 COV | NFCCG COV | Role vs. 13 | Note |
|---|---|---|---|---|---|---|---|
| Emmanwori | 73.9 | 73.3 | 85.4 | 47.6 | 89.9 | Hybrid | Peaked in NFCCG |
| Witherspoon | 90.1 | 83.6 | 55.8 | 53.5 | 61.5 | Coverage + blitz | Faded vs LAR |
| C. Bryant* | 70.3 | 67.2 | 74.3 | 30.1 | 60.5 | Deep coverage | *Signed CHI |
| Okada | 73.1 | 70.0 | 58.3 | 35.2 | 60.4 | Rotation / depth | Wk16 worst game |
| Woolen* | 59.8 | 62.4 | 58.9 | 68.5 | 54.2 | Outside coverage | *Signed PHI |
| Jobe | 57.6 | 52.9 | 58.0 | 70.0 | 52.6 | Outside coverage | Re-signed 3yr |
* Coby Bryant signed with Chicago Bears. Riq Woolen signed with Philadelphia Eagles. (2026 free agency)
Grade key: 75+ elite · 60–74 solid · 50–59 below average · <50 poor
Source: PFF Premium · Full data: outputs/sea_db_pff_grades.csv
Key Finding
Seattle's adaptation to the Rams' 13 personnel was a bet on one player's trajectory.
PFF grades tell the story. Week 11, the Seahawks held the Rams to 2.7 yards per play in 13 personnel and Emmanwori posted an 85.4 coverage grade — his best mark of the regular season at that point. Defense worked; two short-field touchdowns off turnovers gave the Rams the win despite containing the Rams offense.
Week 16 the Rams escalated to 61.4% 13 personnel usage and the secondary buckled. Bryant posted a 30.1 coverage grade. Okada hit 35.2. Witherspoon, Seattle's season-long anchor with a 90.1 overall defensive grade, dropped to 53.5 in coverage. Emmanwori struggled at 47.6. The Seahawks survived overtime, but the Rams put up almost 600 yards of offense with no turnovers.
NFC Championship the Rams went heavy again. Emmanwori delivered the best game of his rookie season: 89.5 defensive grade, 89.9 coverage grade, three pass breakups directly against the Rams' tight end targets. While the rest of the secondary posted middling numbers, Emmanwori excelled and Seattle won 31–27.
Emmanwori Coverage Arc vs. LAR
As the Rams escalated their 13 personnel volume across three games, one player scaled with it. Emmanwori didn't just survive the hardest schematic test in the NFL; he got better. That's personnel philosophy in action — a system that works because of a specific, rare player who can operate at every level of the defense without substitution.
Draft & Roster Implications
The Rams' 13 personnel trend is expected to proliferate in 2026 as other teams adopt heavy tight end packages. Seattle's ability to defend this depends on maintaining the versatile secondary.
Seahawks lost two starters from the Super Bowl defensive backfield in the first week of free agency. Coby Bryant signed with Chicago and Riq Woolen left for Philadelphia. Those are significant losses. Grades add context: Bryant posted a 30.1 coverage grade in Week 16 and Woolen graded at 54.2 in the NFC Championship. Neither player solved the 13 personnel problem in the biggest moments.
Seattle re-signed Josh Jobe on a three-year deal. His Week 16 performance — 70.0 coverage grade — was the best of any Seahawk in that game. Former Colts safety Rodney Thomas II signed a one-year contract with the Seahawks. Thomas started 25 games over two seasons in Indianapolis and posted six interceptions — the kind of ball production that fits what Macdonald asks of his safeties. He'll likely compete with Ty Okada for the starting role Bryant vacated.
The core versatility package remains intact. Emmanwori and Witherspoon are both under contract. Although Witherspoon's coverage grades against the Rams specifically (55.8, 53.5, 61.5) were well below his season mark of 83.6. Not a talent problem — it's a volume problem. When every team in the division runs heavy personnel, the Seahawks need more than one player who can excel defending it at an elite level.
2026 Draft is critical for Seattle to add another hybrid defensive back to complement Emmanwori and sustain the coverage against the Rams. The question is no longer whether the scheme works, but the roster depth after a Super Bowl tax hits them in free agency.
Our follow-up applies the HHI-based versatility score to Emmanwori's rookie deployment data, validating the model against his actual 2025 usage. Then we'll evaluate which 2026 draft prospects have the alignment versatility to fill the gaps Seattle just created.
Methodology & Sources
Personnel grouping data: nflreadpy (load_pbp, load_participation) via nflverse. EPA calculations from nflfastR models. Defensive snap counts and alignment data: PFF Premium. Game-level deployment details supplemented by NFL Next Gen Stats (via seahawks.com), FOX Sports, and NFL.com reporting. All data points are sourced transparently in the text.
Note: Alignment-level snap splits (deep safety / box / slot) are not available through nflverse. Publicly reported alignment percentages from NFL Next Gen Stats are used and noted.