James Harden lost the ball 387 times in 2018-19.

NAME	SEASON	TM	GP	TOV	MPG	PPG	RPG	APG	SPG	BPG	TPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	MIN	PTS	REB	AST	STL	BLK	PF	+/-
James Harden	2018-19	HOU	78	387	36.8	36.1	6.6	7.5	2.0	0.7	5.0	10.8	24.5	44.2	4.8	13.2	36.8	9.7	11.0	87.9	2,867	2,818	518	586	158	58	244	+357
Russell Westbrook	2017-18	OKC	80	381	36.4	25.4	10.1	10.3	1.8	0.3	4.8	9.5	21.1	44.9	1.2	4.1	29.8	5.2	7.1	73.7	2,914	2,028	804	820	147	20	200	+383
James Harden	2016-17	HOU	81	464	36.4	29.1	8.1	11.2	1.5	0.5	5.7	8.3	18.9	44.0	3.2	9.3	34.7	9.2	10.9	84.7	2,947	2,356	659	907	121	38	215	+425
Russell Westbrook	2016-17	OKC	81	438	34.6	31.6	10.7	10.4	1.6	0.4	5.4	10.2	24.0	42.5	2.5	7.2	34.3	8.8	10.4	84.5	2,802	2,558	864	840	132	31	190	+251
James Harden	2015-16	HOU	82	374	38.1	29.0	6.1	7.5	1.7	0.6	4.6	8.7	19.7	43.9	2.9	8.0	35.9	8.8	10.2	86.0	3,125	2,376	501	612	139	51	229	+125
Charles Barkley	1985-86	PHI	80	350	36.9	20.0	12.8	3.9	2.2	1.6	4.4	7.4	13.0	57.2	0.2	0.9	22.7	5.0	7.2	68.5	2,952	1,603	1,026	312	173	125	333
Micheal Ray Richardson	1979-80	NYK	82	359	37.3	15.3	6.6	10.1	3.2	0.4	4.4	6.1	13.0	47.2	0.3	1.3	24.5	2.7	4.1	66.0	3,060	1,254	539	832	265	35	260
Artis Gilmore	1977-78	CHI	82	366	37.4	22.9	13.1	3.2	0.5	2.2	4.5	8.6	15.4	55.9				5.7	8.2	70.4	3,067	1,879	1,071	263	42	181	261
Kevin Porter	1977-78	TOT	82	360	34.3	15.0	2.6	10.2	1.5	0.2	4.4	6.0	12.9	46.9				3.0	3.9	76.3	2,813	1,234	214	837	123	15	283
Ricky Sobers	1977-78	IND	79	352	38.2	18.2	4.1	7.4	2.2	0.3	4.5	7.0	15.5	45.3				4.2	5.1	82.5	3,019	1,436	327	584	170	23	308

StatMuse has season-level data for turnovers going back to the 1977-78 season.