When Mike Trout reported to spring training in mid-February 2020, he was 28 years old and had more career WAR through the age of 27 than any player in Major League Baseball history.
Although 27 has long been mythologized (not entirely accurately) as the peak of Major League Baseball players' performance, it's not as though year 28 automatically triggers some inexorable decline. Babe Ruth had his best season at 28. So did Rogers Hornsby and Ernie Banks, and until his PED-fueled third act, Barry Bonds' best season had come at 28. Other inner-circle stars -- Joe Morgan and Albert Pujols among them -- set new career highs at 28 and then continued to improve.