All city: New York 1948.

1948 all New York City selections are in bold.  Lefty pitchers are in Italics.  Pyth is Pythagorean W-L (estimate of a team's winning percentage given their runs scored and runs allowed).  Comments below.  Click link to view data for years 1947-1957.  Seeing the players in a matrix may have some surprises.  Batting data below sorted by OPS+ per team.

1948	New York Giants	Brooklyn Dodgers	New York Yankees
C	Walker Cooper	Roy Campanella	Gus Niarhos
1B	Johnny Mize	Gil Hodges	George McQuinn
2B	Bill Rigney	Jackie Robinson	Snuffy Stirnweiss
SS	Buddy Kerr	Pee Wee Reese	Phil Rizzuto
3B	Sid Gordon	Billy Cox	Billy Johnson
LF	Whitey Lockman	Marv Rackley	Johnny Lindell
CF	Bobby Thomson	Carl Furillo	Joe DiMaggio
RF	Willard Marshall	Gene Hermanski	Tommy Henrich
P	Larry Jansen	Rex Barney	Allie Reynolds
P	Dave Koslo	Preacher Roe	Eddie Lopat
P	Ray Poat	Ralph Branca	Vic Raschi
P	Clint Hartung	Joe Hatten	Spec Shea
Man.	Mel Ott/Leo Durocher	Leo Durocher/Burt Shotton	Bucky Harris
W-L	78-76	84-70	94-60
Pyth	84-70	84-70	98-56
Dif	-6	0	-4
Rank	5	3	3
WS
Attend.	1,459,269	1,398,967	2,373,901
Att rank	3	4	2
1948	New York Giants	Brooklyn Dodgers	New York Yankees

Rk	Pos		Age	G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	OPS+ ▾	TB	GDP	HBP	SH	SF	IBB
1	1B	Johnny Mize*	35	152	658	560	110	162	26	4	40	125	4		94	37	.289	.395	.564	.959	156	316	7	4	0
2	3B	Sid Gordon	30	142	605	521	100	156	26	4	30	107	8		74	39	.299	.390	.537	.927	147	280	18	3	7
3	OF	Whitey Lockman*	21	146	659	584	117	167	24	10	18	59	8		68	63	.286	.361	.454	.815	118	265	4	1	6
4	C	Walker Cooper	33	91	319	290	40	77	12	0	16	54	1		28	29	.266	.332	.472	.805	115	137	14	1	3
5	OF	Willard Marshall*	27	143	605	537	72	146	21	8	14	86	2		64	34	.272	.350	.419	.769	107	225	11	1	2
6	2B	Bill Rigney	30	113	478	424	72	112	17	3	10	43	4		47	54	.264	.342	.389	.731	97	165	9	3	4
7	OF	Bobby Thomson	24	138	507	471	75	117	20	2	16	63	2		30	77	.248	.296	.401	.697	86	189	15	2	3
8	IF	Jack Lohrke	24	97	314	280	35	70	15	1	5	31	3		30	30	.250	.323	.364	.687	85	102	6	0	4
9	SS	Buddy Kerr	25	144	555	496	41	119	16	4	0	46	9		56	36	.240	.317	.288	.605	64	143	7	0	3

Rk	Pos		Age	G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	OPS+ ▾	TB	GDP	HBP	SH	SF	IBB
1	OF	Gene Hermanski*	28	133	471	400	63	116	22	7	15	60	15		64	46	.290	.391	.493	.883	134	197	7	2	4
2	2B	Jackie Robinson	29	147	648	574	108	170	38	8	12	85	22		57	37	.296	.367	.453	.820	117	260	7	7	8
3	OF	Carl Furillo	26	108	414	364	55	108	20	4	4	44	6		43	32	.297	.374	.407	.781	108	148	7	2	5
4	UT	Bruce Edwards	24	96	319	286	36	79	17	2	8	54	4		26	28	.276	.341	.434	.774	105	124	10	2	4
5	C	Roy Campanella	26	83	320	279	32	72	11	3	9	45	3		36	45	.258	.345	.416	.761	102	116	3	1	5
6	SS	Pee Wee Reese	29	151	655	566	96	155	31	4	9	75	25		79	63	.274	.363	.390	.753	100	221	16	0	9
7	1B	Gil Hodges	24	134	527	481	48	120	18	5	11	70	7		43	61	.249	.311	.376	.687	82	181	11	0	4

Rk	Pos		Age	G	PA	AB	R	H	2B	3B	HR	RBI	SB	CS	BB	SO	BA	OBP	SLG	OPS	OPS+ ▾	TB	GDP	HBP	SH	SF	IBB
1	OF	Joe DiMaggio	33	153	669	594	110	190	26	11	39	155	1	1	67	30	.320	.396	.598	.994	163	355	20	8	0
2	OF	Tommy Henrich*	35	146	674	588	138	181	42	14	25	100	2	3	76	42	.308	.391	.554	.945	151	326	14	4	5
3	OF	Johnny Lindell	31	88	344	309	58	98	17	2	13	55	0	0	35	50	.317	.387	.511	.898	138	158	8	0	1
4	UT	Yogi Berra*	23	125	497	469	70	143	24	10	14	98	3	3	25	24	.305	.341	.488	.830	120	229	9	1	2
5	3B	Billy Johnson	29	127	493	446	59	131	20	6	12	64	0	0	41	30	.294	.358	.446	.805	114	199	22	4	1
6	IF	Bobby Brown*	23	113	417	363	62	109	19	5	3	48	0	1	48	16	.300	.383	.405	.788	111	147	7	1	4
7	1B	George McQuinn*	38	94	346	302	33	75	11	4	11	41	0	2	40	38	.248	.336	.421	.757	101	127	5	0	4
8	2B	Snuffy Stirnweiss	29	141	609	515	90	130	20	7	3	32	5	4	86	62	.252	.360	.336	.696	86	173	13	1	8
9	SS	Phil Rizzuto	30	128	539	464	65	117	13	2	6	50	6	5	60	24	.252	.340	.328	.668	79	152	6	2	13

Johnny Mize Baseball Digest, inside front cover
March 1948 via Wikimedia

The Yankees and Dodgers were evolving into the famous teams we remember.  This is the only season in this series from 1947 through 1957 when no New York team played in the World Series.  1948 and 1952 are the only seasons when no New York player was voted MVP.

Joe DiMaggio led the AL with 39 homers, the second and last time he was home run king.

Gus Niarhos was barely the starting catcher for the Yankees as Yogi Berra still played a lot in the outfield.

Roy Campanella and Gil Hodges became starters for the Dodgers and Jackie Robinson moved to his natural position, second base, for the first of five seasons.

Leo Durocher started 1948 managing the Dodgers and finished managing the Giants.

Johnny Mize tied Pirate Ralph Kiner for the NL lead in homers for the second year in a row: 51 and 40.  New York had the home run champs in both leagues in 1948.