Barry Bonds, circa 1997

So, I was flipping through the STATS 1997 Baseball Scoreboard and came across a fun article about Barry Bonds on pages 73-75. The question asked was this: “What will the rest of Bonds’ career look like?”

As a reminder, here is what Bonds had done through 1996:

G	AB	R	H	2B	3B	HR	RBI	BB	SB	BA	OBP	SLG
1583	5537	1121	1595	333	51	334	993	1082	380	.288	.404	.548

The article then used Bill James’ Brock6 system to project the remainder of Bonds’ career. Here’s a year-by-year look at Brock6’s projections in 1997 versus what Bonds actually did (I’m including only the stats that were provided in the original article):

1997

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	526	113	149	38	109	131	34	.283
actual	532	123	155	40	101	145	37	.291

Looks about right to me. The projection is peering only one year into the future, so most of the inputs are known and we should expect it to be reasonably accurate.

1998

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	520	110	144	36	108	138	33	.277
actual	552	120	167	37	122	130	28	.303

The projection underestimates Bonds’ batting average, but otherwise this is pretty spot on.

1999

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	506	108	138	34	105	138	32	.273
actual	355	91	93	34	83	73	15	.262

Okay, here’s the drop in batting average. This isn’t surprising given Bonds’ age—he’s 34 years old now, so some slippage should be expected. Same with the stolen bases. The projection does nail homers (though Bonds reaches the predicted total in 151 fewer at-bats).

2000

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	492	102	132	32	98	132	30	.268
actual	480	129	147	49	106	117	11	.306

Nice rebound season for Bonds. The power spike in ’99 was legitimate, and his batting average is back to where it was in ’98. Again, stolen bases are declining, which is fine for a guy in his mid-30s.

2001

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	476	95	126	30	93	130	28	.265
actual	476	129	156	73	137	177	13	.328

I love the fact that James nailed the at-bats. The rest of these numbers are pretty far out of whack. Conditions change, and the best forecasting systems may not be able to account for this.

2002

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	459	90	120	28	88	127	27	.261
actual	403	117	149	46	110	198	9	.370

A year after breaking the single-season home-run record, Bonds wins his first NL batting title, at age 37.

2003

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	443	84	114	26	81	123	23	.257
actual	390	111	133	45	90	148	7	.341

The huge disconnect between projection and reality continues.

2004

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	426	79	107	24	76	120	22	.251
actual	373	129	135	45	101	232	6	.362

Bonds wins the second of two career NL batting titles and demolishes the single-season record for walks. He is now 39.

2005

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	410	74	101	22	71	117	20	.246
actual	42	8	12	5	10	9	0	.286

Bonds is hurt.

2006

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	392	68	95	20	66	113	18	.242
actual	367	74	99	26	77	115	3	.270

At age 41, Bonds finally begins his decline phase. This is roughly the season that Brock6 predicted for Bonds in 2002, when Bonds won his first batting title.

2007

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	327	55	78	14	52	95	14	.239
actual	340	75	94	28	66	132	5	.276

The projection has Bonds declining further, while reality has Bonds repeating his ’06 performance.

2008

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	226	37	53	9	35	66	9	.235
actual	reply hazy, try again

If he gets the chance, Bonds will beat this projection.

Career

	AB	R	H	HR	RBI	BB	SB	BA
Brock6	10740	2136	2952	647	1975	2512	670	.275
actual	9847	2227	2935	762	1996	2558	514	.298

This is a remarkably accurate career projection. Brock6 nailed the hits, RBI and walks, and it wasn’t too far off on runs scored. It missed badly on homers, stolen bases and batting average.

In hindsight, it probably was a bit much to expect Bonds to continue stealing 20+ bases a year into his late 30s. As for the jump in home runs… I have a theory, but it’s not particularly original. In fact, you’ve probably heard it from every single person on the planet already, so we’ll just leave it at that.