No. 3 Brandon Belt
Brandon Belt has been in the Majors since 2011, the same year as Mike Trout. While he hasn't played like Mike Trout, he has had an above-average career so far with a career OPS+ of 124, compared to the league average of 100.
While struggling last season, he has completely rebounded this season with the Blue Jays. In 96 games, he has an average of .252 and an on-base percentage of .371, while slugging 16 home runs. His OPS is an elite .844. While he doesn't have a long-term future at first base due to his age, he could be a good short-term player worth around $5-15 million a year. Acquiring him in free agency could be a steal.