who had the most 20 game seasons by a pitcher

Nolan Ryan has played the most career seasons, with 27 seasons.

	NAME	SEAS	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Nolan Ryan N. Ryan	27	807	324	292	.526	773	3.19	5,714	222	61	3	5386.0	3,923	1,911	2,178	321	2,795	158	13	78	22,575	277	9.55	4.67	2.04	0.54	25.3	12.4	1.25	.265	3.64	90	2.96	83	6.56	370.2
2	Tommy John T. John	26	760	288	231	.555	700	3.34	2,245	162	46	3	4710.1	4,783	1,749	2,017	302	1,259	98	22	102	19,692	187	4.29	2.41	1.78	0.58	11.4	6.4	1.28	.284	3.85	90	3.37	89	9.14	208.3
3	Deacon McGuire D. McGuire	26	1	0	0		0	6.75	1	0	0	0	4.0	10	3	5	0	1		1		23	1	2.25	2.25	1.00	0.00	4.3	4.3	2.75	.476	11.25	184	3.17	92	22.50	0.1
4	Jamie Moyer J. Moyer	25	696	269	209	.563	638	4.25	2,441	33	10	0	4074.0	4,231	1,926	2,076	522	1,155	146	15	69	17,356	57	5.39	2.55	2.11	1.15	14.1	6.7	1.32	.283	4.59	97	4.46	102	9.35	-33.5
5	Rickey Henderson R. Henderson	25
6	Charlie Hough C. Hough	25	858	216	216	.500	440	3.75	2,362	107	13	61	3801.1	3,283	1,582	1,807	383	1,665	174	240	44	16,170	179	5.59	3.94	1.42	0.91	14.6	10.3	1.30	.250	4.28	95	4.28	109	7.77	-142.3
7	Jim Kaat J. Kaat	25	898	283	237	.544	625	3.45	2,461	180	31	17	4530.1	4,620	1,738	2,038	395	1,083	122	102	116	19,023	128	4.89	2.15	2.27	0.78	12.9	5.7	1.26	.282	4.05	93	3.41	91	9.18	165.8
8	Eddie Collins E. Collins	25
9	Bobby Wallace B. Wallace	25	57	24	22	.522	48	3.87	120	37	3	1	402.0	469	173	268	6	156	13	9		1,799	16	2.69	3.49	0.77	0.13	6.7	8.7	1.55	.308	6.00	80	4.35	90	10.50	23.5
10	Omar Vizquel O. Vizquel	24
11	Roger Clemens R. Clemens	24	709	354	184	.658	707	3.12	4,672	118	46	0	4916.2	4,185	1,707	1,885	363	1,580	159	0	63	20,240	143	8.55	2.89	2.96	0.66	23.1	7.8	1.17	.284	3.45	70	3.08	71	7.66	680.4
12	Jesse Orosco J. Orosco	24	1,252	87	80	.521	4	3.16	1,179	0	0	144	1295.1	1,055	455	512	113	581	34	501	86	5,460	40	8.19	4.04	2.03	0.79	21.6	10.6	1.26	.265	3.56	80	3.60	91	7.33	52.1
13	Dennis Eckersley D. Eckersley	24	1,071	197	171	.535	361	3.50	2,401	100	20	390	3285.2	3,076	1,278	1,382	347	738	75	577	91	13,534	28	6.58	2.02	3.25	0.95	17.7	5.5	1.16	.274	3.79	86	3.40	85	8.43	224.9
14	Rick Dempsey R. Dempsey	24	2	0	0		0	4.50	0	0	0	0	2.0	3	1	1	0	1	0	2	0	10	0	0.00	4.50	0.00	0.00	0.0	10.0	2.00	.333	4.50	112	4.35	110	13.50	-0.1
15	Carlton Fisk C. Fisk	24
16	Steve Carlton S. Carlton	24	741	329	244	.574	709	3.22	4,136	254	55	2	5217.2	4,672	1,864	2,130	414	1,833	53	13	150	21,683	183	7.13	3.16	2.26	0.71	19.1	8.5	1.25	.279	3.67	87	3.14	86	8.06	271.5
17	Phil Niekro P. Niekro	24	864	318	274	.537	716	3.35	3,342	245	45	29	5404.0	5,044	2,012	2,337	482	1,809	123	83	86	22,677	226	5.57	3.01	1.85	0.80	14.7	8.0	1.27	.270	3.89	87	3.61	95	8.40	116.1
18	Pete Rose P. Rose	24
19	Ty Cobb T. Cobb	24	3	0	0		0	3.60	0	0	0	1	5.0	6	2	2	0	2	0	2		20	0	0.00	3.60	0.00	0.00	0.0	10.0	1.60	.333	3.60	130	3.61	119	10.80	-0.3
20	Greg Maddux G. Maddux	23	744	355	227	.610	740	3.16	3,371	109	35	0	5008.1	4,726	1,756	1,981	353	999	137	3	177	20,421	70	6.06	1.80	3.37	0.63	16.5	4.9	1.14	.281	3.56	76	3.25	78	8.49	519.5
21	Julio Franco J. Franco	23
22	Tim Raines T. Raines	23
23	Dennis Martinez D. Martinez	23	692	245	193	.559	562	3.70	2,149	122	30	8	3999.2	3,897	1,643	1,835	372	1,165	122	51	71	16,754	83	4.84	2.62	1.84	0.84	12.8	7.0	1.27	.272	4.13	94	3.91	99	8.77	17
24	Don Sutton D. Sutton	23	774	324	256	.559	756	3.26	3,574	178	58	5	5282.1	4,692	1,914	2,104	472	1,343	82	12	102	21,631	112	6.09	2.29	2.66	0.80	16.5	6.2	1.14	.261	3.58	92	3.23	90	7.99	181.2
25	Tony Perez T. Perez	23