The Saber's Edge: Analyzing PA Projections

The Saber's Edge: Analyzing PA Projections

This article is part of our The Saber's Edge series.

Playing time influences all of a hitter's stats, but it is probably one of the least understood. An extra 100 plate appearances is equivalent to about a month of playing time. We project Alex Gordon to make 521 plate appearances, but he could easily surpass 600 like he did for four straight seasons (2011 to 2014) if he remains healthy. What are his chances of beating the projection? This week, I will investigate plate-appearance projection accuracy and any advantages gained from that information.

I chose Steamer's historic projections as a test group. One data anomaly I found immediately was that the projected number of plate appearances ran a little high; I talked to the creator of Steamer, Jared Cross, who said he wasn't aware of the issue but will look into it.

Even with the small bias, Steamer is considered the most accurate projection system and is always upgrading, such as using pitch velocity as an input. It's a perfect projection system for today's study.

The Steamer projections go back to 2010, and the plate-appearance numbers are derived from FanGraphs fan playing time estimates and depth charts.

To start, here are the plate-appearance distributions compared to the actual results by percentiles.

PAPERCENTILES90%75%50%25%10%COUNT
>700 Projected 738 722 708 705 702 23
Actual 716 709 674 511 351
651 to 700 Projected 689 680 666 656 652 183
Actual 700 681 648 573 425
601 to 650 Projected 647 637 625 614 606 340
Playing time influences all of a hitter's stats, but it is probably one of the least understood. An extra 100 plate appearances is equivalent to about a month of playing time. We project Alex Gordon to make 521 plate appearances, but he could easily surpass 600 like he did for four straight seasons (2011 to 2014) if he remains healthy. What are his chances of beating the projection? This week, I will investigate plate-appearance projection accuracy and any advantages gained from that information.

I chose Steamer's historic projections as a test group. One data anomaly I found immediately was that the projected number of plate appearances ran a little high; I talked to the creator of Steamer, Jared Cross, who said he wasn't aware of the issue but will look into it.

Even with the small bias, Steamer is considered the most accurate projection system and is always upgrading, such as using pitch velocity as an input. It's a perfect projection system for today's study.

The Steamer projections go back to 2010, and the plate-appearance numbers are derived from FanGraphs fan playing time estimates and depth charts.

To start, here are the plate-appearance distributions compared to the actual results by percentiles.

PAPERCENTILES90%75%50%25%10%COUNT
>700 Projected 738 722 708 705 702 23
Actual 716 709 674 511 351
651 to 700 Projected 689 680 666 656 652 183
Actual 700 681 648 573 425
601 to 650 Projected 647 637 625 614 606 340
Actual 691 665 595 503 361
551 to 600 Projected 596 586 575 561 556 394
Actual 668 626 547 415 275
501 to 550 Projected 546 541 529 514 506 297
Actual 641 590 493 340 194
451 to 500 Projected 495 485 474 461 453 235
Actual 603 531 439 321 239
401 to 450 Projected 446 438 427 416 407 186
Actual 578 492 399 259 136
351 to 400 Projected 398 388 374 360 355 163
Actual 503 429 328 219 103
301 to 350 Projected 343 335 322 310 305 155
Actual 537 418 273 166 68
251 to 300 Projected 293 283 273 262 255 230
Actual 511 367 255 161 105

Thoughts on this data:

With a 30-PA bias factored in, the 10th and 25th percentiles see a significant drop in plate appearances. Owners should expect at least a 33 percent drop in projected plate appearances for at least 25 percent of their full-time players. And for 10 percent of the hitters, the drop is 41 percent. Basically, on a normal 14-man lineup, three to four hitters will not live up to expectations, with one to two seeing a huge drop.

While the players projected for at least 600 PA don't have a ton of upside, the players from 450 to 600 do. This group contains injury-prone players like Giancarlo Stanton and Alex Gordon, who could stay healthy for the season and collect 650 PA … or could get injured again.

Anyone with less than 400 projected plate appearances usually doesn't break out for full-season playing time. The low 500s is the best-case estimate.

On to the next table, which contains the projected OPS for each plate-appearance bucket:

PA BUCKETPROJECTED
MEDIAN OPS
ACTUAL
MEDIAN OPS
DIFFERENCE
>700 .850 .839 -.011
651 to 700 .810 .789 -.021
601 to 650 .780 .767 -.013
551 to 600 .759 .737 -.023
501 to 550 .742 .721 -.021
451 to 500 .738 .726 -.012
401 to 450 .722 .693 -.029
351 to 400 .703 .689 -.014
301 to 350 .700 .684 -.016
251 to 300 .697 .659 -.038

No surprises with this table. The best players get the most plate appearances. A small drop in performance exists, but the projections are solid.

For this next table, I divided out players from each plate appearance bucket by OPS. I set the dividing mark at .780 OPS, which is the average value for hitters with 600-plus plate appearances. Only three players were below the mark in the 700-plus bucket, so I ignored that group.

PA BUCKETPA PERCENTILE90%75%50%25%10%
651 to 700 High OPS 705 682 649 574 443
Low OPS 698 675 640 573 391
Diff 7 7 9 1 52
601 to 650 High OPS 695 667 613 505 365
Low OPS 688 658 583 499 354
Diff 7 9 30 6 11
551 to 600 High OPS 666 626 558 436 317
Low OPS 672 630 543 399 244
Diff -6 -4 15 37 73
501 to 550 High OPS 648 610 512 357 235
Low OPS 626 584 493 336 190
Diff 22 26 19 21 45
451 to 500 High OPS 650 534 448 344 278
Low OPS 594 526 438 313 239
Diff 56 8 10 31 39
401 to 450 High OPS 585 522 441 238 146
Low OPS 563 491 398 260 136
Diff 22 31 43 -22 10
351 to 400 High OPS 441 402 324 242 63
Low OPS 503 431 332 219 103
Diff -62 -29 -8 23 -40
301 to 350 High OPS 649 478 244 192 185
Low OPS 521 415 274 165 65
Diff 128 63 -30 27 120
251 to 300 High OPS 442 285 210 161 118
Low OPS 514 373 258 162 105
Diff -72 -88 -48 -1 13

Thoughts on this table:

Anyone projected for more than 600 PA will play no matter his projected OPS. These weak hitters are probably defensive wizards who continue to play because of their gloves, not their bats.

From about 400 to 550 projected plate appearances, the cream rises to the top, with the better hitters getting about 20 to 30 additional plate appearances.

Because of the uncertain playing time, it's each owner's responsibility to have a good handle on projected plate appearances. A player who opens the season on the DL will see his plate appearances drop, naturally. The difference may seem small, but they can add up when multiple players are adjusted.

Here are some situations to monitor with the hitters' potential playing time in flux:

Any Cub without the last name Rizzo or Bryant: The Cubs' roster contains too many MLB-caliber players and not enough lineup spots to go around. (This situation was even more of a mess before Jorge Soler was traded to the Royals.) Ben Zobrist, Addison Russell and Javier Baez will be splitting time between the two middle-infield spots; Zobrist joins Jason Heyward, Jon Jay, Albert Almora and Kyle Schwarber in the outfield mix. If everyone stays healthy, that could mean 450 plate appearances each.

Jung Ho Kang: Kang didn't receive any jail time for his DUI in Korea. He still may miss time, as the team or league may suspend him, but no news on the situation has come out yet.

Albert Pujols and Michael Brantley: Neither has played in spring games yet. Pujols is getting close to his first action, but Brantley is not close at all.

Plate appearances remain a dull topic. They're not home runs, RBI or stolen bases. But in truth, they are. The more plate appearances a player makes, the more chances he has to accumulate precious fantasy stats. By diligently tracking changes in plate appearances, we can identify players to target and avoid on draft day.

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ABOUT THE AUTHOR
Jeff Zimmerman
Zimmerman writes analytics-focused baseball and football articles for RotoWire. He is a three-time FSWA award winner, including the Football Writer of the Year and Best Football Print Article awards in 2016. The 2017 Tout Wars Mixed Auction champion and 2016 Tout Wars Head-to-Head champ, Zimmerman also contributes to FanGraphs.com, BaseballHQ and Baseball America.
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