Cody Bellinger's decline the last three years might be largest ever based on age

He had an OPS+ of 144 during his age 21-23 seasons while it was only 74 during his age 24-26 seasons. Where does that decrease of 70 rank?

Here is something from Alden Gonzalez of ESPN that might be an explanation:

"On the heels of an MVP award and coming off the COVID-19-shortened spring training, Bellinger rejoined the Dodgers in the summer of 2020 with an overhauled batting stance that he struggled with throughout the shortened season. He then suffered a shoulder injury during a home run celebration in the NL Championship Series that necessitated offseason surgery."

See Dodgers non-tender Cody Bellinger, making him a free agent.

I used Stathead to find all of the players who had at least a 130 OPS+ with 1,000+ PAs from age 21-23 in the AL/NL since 1900. Then I checked each of them one-by-one to find their OPS+ during their age 24-26 seasons. Table 1 below shows the worst declines:

Table  1

Player	OPS+ 21-23	OPS+ 24-26	Diff
Cody Bellinger	144	74	-70
Yasiel Puig	151	111	-40
Curt Blefary	133	97	-36
Eddie Mathews	171	139	-32
Dick Wakefield	149	118	-31
Fred Snodgrass	132	104	-28
Sam Crawford	159	132	-27
Jeff Burroughs	146	121	-25
Tony Conigliaro	130	105	-25
Arky Vaughan	161	141	-20
Cal Ripken Jr.	136	117	-19
Joe Morgan	131	112	-19
Ross Youngs	144	125	-19

 

Some players who came up in the age 21-23 were not included in putting together this table for reasons like military service (Ted Williams in WW II who did not play at all from age 24-26) and active young players like Juan Soto who has not yet had his age 24 seasons. 

My plan was to show the largest 10 decreases. But there are 13 listed because for 3 of the players in Table 1 were special circumstances. 

Wakefield did not play in 1945 since he was in the military and that would have been his age 24 season. Also, his 1943-44 numbers might have been inflated a bit with lesser competition and weaker pitching. Conigliaro did not play in 1968, his age 23 season, because of his injury the year before. Morgan only played 10 games in his age 24 season.

All of the other players in Table 1 had 1,000+ PAs during their age 24-26 seasons.

I also looked at two slightly different but similar age profiles: 20-22 vs. 23-25 and 22-24 vs. 25-27. Table 2 has the 20-22 vs. 23-25 numbers:

Table 2

Player	20-22 OPS+	23-25 OPS+	Diff
Curt Blefary	140	108	-32
Jack Fournier	149	117	-32
Carlos Correa	137	110	-27
Bryce Harper	154	133	-21
Tony Conigliaro	131	111	-20
Stuffy McInnis	132	115	-17
Al Kaline	140	129	-11
Cody Bellinger	131	122	-9
Boog Powell	133	126	-7
Cesar Cedeno	136	133	-3
Sam Crawford	144	141	-3
Ross Youngs	136	136	0

Again, I meant to have only the 10 largest declines. But, as stated above, Conigliaro did not play in his age 23 season. Fournier only had 111 PAs from age 23-25, which he spent mostly in the minors. All of the other players in Table 2 had 1,000+ PAs during their age 23-25 seasons.

Table 3 shows the 22-24 vs. 25-27 numbers.

Table 3

Player	22-24 OPS+	25-27 OPS+	Diff
Cody Bellinger	139	64	-75
Mike Greenwell	153	117	-36
Vic Saier	138	103	-35
Jimmy Sheckard	151	117	-34
Bob Robertson	134	101	-33
Arky Vaughan	161	131	-30
John Olerud	146	117	-29
Yasiel Puig	141	114	-27
Dick Wakefield	149	122	-27
Shoeless Joe Jackson	193	167	-26
Kal Daniels	154	131	-23
Bryce Harper	156	134	-22
Larry Doyle	140	119	-21

  

Bellinger only has 900 PAs from age 25-27. Saier only had 614, due to injuries and working in a defense plant during WWI. Wakefield's war service was mentioned earlier. Again, everyone else has at least 1,000 PAs from age 25-27 in Table 3. 

Bellinger's decline of 70 in OPS+ is well ahead of everyone else. The closest decline is Puig with -40. Maybe someone who had an OPS+ under 130 from age 21-23 saw an even larger decline. But I wanted to focus on high quality hitters by setting 130 as the cutoff to capture similar players. That means that maybe I should have not included anyone with an OPS+ over 160. But no one like that shows up in my tables.

I found all the guys who had 500+ PAs from age 24-26 and an OPS+ of 60 or less (if a guy had a 129 OPS+ from age 21-23 and fell 70, he would have a 59 OPS+ from age 24-26, so anyone above 60 could not have a decline of 70 or more otherwise I would have found them already since that would mean an OPS+ of at least 130 from age 21-23). I used only 500 PAs to take into account guys who might have had their playing time cut because they were hitting so poorly.

There were 88 guys on the list and I checked them one-by-one to see what their OPS+ was from age 21-23 (and to see if they had 1,000+ PAs in that time). Some guys did not get that many PAs from 21-23. For the others, the largest decline I found was 16.

Only 4 of the 88 had 1,000+ PAs from age 21-23. Here they are with their OPS+ at the different ages

Alfredo Griffin Age 21-23 OPS+ 72 & Age 24-26 OPS+ 59

Enzo Hernandez Age 21-23 OPS+ 57 & Age 24-26 OPS+ 55

Tommy Thevenow  Age 21-23 OPS+ 53 Age 24-26 OPS+ 46

Hal Lanier Age 21-23 OPS+ 58 Age 24-26 OPS+ 42 (that is the decline of 16)

Since no one in this group of 88 fell as much as Bellinger, then his fall has to be the highest, at least when comparing 21-23 vs. 24-26