Currently on a pace that almost reaches only long time super well known steroid cheaters, Exception? Babe Ruth?
Per at Bat HRs:
Single-season statistics are current as of July 2021.[2]
k Player (age that year) AB per HR Year PA Bats
1. Barry Bonds (36) 6.52 2001 664 L
2. Mark McGwire (34) 7.27 1998 681 R
3. Josh Gibson+ (25) 7.80 1937 183 R
4. Mark McGwire (35) 8.02 1999 661 R
5. Mark McGwire (32) 8.13 1996 548 R
6. Barry Bonds (39) 8.29 2004 617 L
7. Babe Ruth+ (25) 8.48 1920 617 L
8. Barry Bonds (38) 8.67 2003 550 L
9. Barry Bonds (37) 8.76 2002 612 L
10. Babe Ruth+ (32) 9.00 1927 691 L
11. Sammy Sosa (32) 9.02 2001 711 R
12. Babe Ruth+ (26) 9.15 1921 693 L
13. Aaron Judge (30) 9.18 2022
Link:
Single-Season Leaders & Records for AB per HR | Baseball-Reference.com