He is at 9.9, tying him for the 47th best season with Ernie Banks (1959) and Rogers Hornsby (1927). Trout bats leadoff and last year in the AL leadoff men got 6-7% more walks + ABs than a cleanup hitter (I guess that most of the great seasons were by 3 and 4 hitters). Should we reduce his offensive WAR by that much to equalize things? I don't know, but even if we did, it would only lower his offensive WAR to 6.862 (I lowered it 6%). But with his defensive WAR of 2.7, it would still leave him with a WAR of 9.5-9.6, tied for no worse than 64th. If we stick with his WAR of 9.9, the only players to ever have a better season than that who are not in the Hall of Fame are Barry Bonds, Sammy Sosa and Alex Rodriguez.
Update: Through games of Sept. 10, he is at 10.2. That is tied for the 28th best season ever. Fangraphs has him at "only" 8.6. But that is just in 118 games. If he did that for 162 games, it would be 11.8, good enough for the 23rd best season ever at Fangraphs. Over 154 games, it would be 11.2, tied for the 32nd best season ever. Going back to Baseball Reference, if Trout kept up his pace this year for 162 games, he would have 14 WAR, beating Ruth's record of 13.7 in 1923. Over 154 games. Trout would get 13.3 and that would be 2nd to Ruth. If Trout keeps up his current pace over the last 21 games, he will finish with a WAR of about 12. That would tie Hornsby and Yastrzemski for the 4th best season ever. Trout had one game where he pinch ran in the 8th inning and the game ended in the 9th. He had no putouts or PAs or SBs.
Update: Through games of Sept. 11 he is at10.4, tied for the 24th best season ever with Yount (1982) and Bonds (2004). If he can make it to 11.4, he will crack the top 10. Not too easy, since it would be a WAR of about 1.0 in 20 games or 8 for a full season. He is obviously capable of that, of course.
Update: Through games of Sept. 20 he is at 10.1. Over his last 8 games, he has been .3 below replacement. He was 6 for 30 in those 8 games with just 1 extra-base hit (2B), 5 BBs and 1 SB.
Update: Through games of Sept. 22 he is at 10.4.
Update: Through games of Sept. 26 he is at 10.6. That is tied for 22nd with Ty Cobb (1911) and Rogers Hornsby (1921). Trout has only played 132 games this year. Only 12 players have ever had a season of 10.6 or higher before Trout. They are
Update: Through games of Sept. 27 he is back down to 10.5. So he falls to 24th place.
Update: Through games of Sept. 28 he is back down to 10.4 even though he was 2 for 5 with a HR and a 3B. So he falls to a tie for 24th place.
Update: Through games of Sept. 30 he is back up to 10.5. The Angels played a doubleheader on Sept 30 after being rained out the day before.
Update: Through games of Oct. 1 he is up to 10.7. That is tied for 20th with Mays (1964) and Williams (1946)