|Age 19-23 Totals||2839||155||29.6|
|Age 19-23 Totals||2877||169||38.1|
Trout has better numbers thru age 23. Mantle's highest OPS+ was 180 while Trout's was 179. But Trout's next best was 175 while Mantle's was 162. Trout has a big edge in career OPS. That might be misleading since Mantle had many more PAs at age 19, and we would not expect too much from a player so young. That might depress Mantle's averages.
If we look at ages 20-23, Trout leads in OPS+, 173-162. So he still has a solid edge in hitting.
But at age 24, Mantle won the triple crown and had an OPS+ of 210. Trout is 24 this year and he is at 183 so far. To finish with 210 this year, he would need to be close to 220 the rest of the season.
Mantle got off to a sensational start that year (at age 24), batting over .400 in both April (11 games) and May (31 games). His SLG was over .800 in both months as well.
At both age 23 and 24, Mantle had big gains in OPS+ (22 and 30, respectively). If Trout has a gain of 30 this year, that would give him a 205, not too far off from Mantle's 210.
Mantle went on to have two other seasons in his career with OPS+ over 200, plus one at 195. He finished with 172. Trout is at 169 in his career so far, not too far behind. But he will have a decline phase later in his career. So to stay close to Mantle, he will have to have some high OPS+ numbers at some point. Can Trout also have three seasons over 200? If he does, that would put him on a par with Mantle.