There are 18 teams in the Florida Complex league. Those teams rostered 72 hitters this season playing in their age-18 year. The PMB Birds had 4, exactly their fair share. The average age for hitters in the league was 19.9 (about a month shy of 20). Cardinals' hitters averaged 19.5 (19 and 6 months). The four 18-year-old players were:
Roblin Heredia, Catcher,
Jake Burns, Catcher,
Jeremy Rivas, Shortstop,
Joshua Baez, Centerfielder.
The club drafted Baez with its 2nd pick in the 2021 draft. The club signed the others as international free agents. Jake Burns is Australian.
The first issue is playing time. It is better if these players played more, theoretically earning time in games and competing. Heredia (139) and Burns (133) saw the most PAs of 18-year-old catchers, and they were top 15 for all 18-year-old hitters. Rivas (200) saw the second most PAs of any 18-year-old, and the most by a shortstop. Baez (95) was 6th most in CF and 34th of 72 overall. Early in the season, Heredia also had about 70 PAs in low A ball. The playing time was a good sign for these four, especially since they all play premium positions.
The next issue is how well they hit. As young players, even in the Florida Complex League, hitting could be difficult. Results in the complex are tricky. They may face someone rehabbing from the majors or high minors or they might face a raw young player. The sample sizes are small, with 200 PAs a big sample. Still, the results provide some information.
Heredia, Burns, and Baez struck out a lot but walked a lot too. Heredia had a 16.5% walk rate and 32.4% K rate. Burns was 13.5% and 27.1%. Baez was 14.7% and 29.5%. Those are all encouraging walk rates and discouraging K rates. For 18-year-old hitters, the median K% was 27.1% so that gives some perspective. The median BB% was 11.5%. Heredia, Burns, and Baez were not major outliers in their rates, even if they were not ideal.
Jeremy Rivas had a different approach. He struck out 16% of the time and walked 7.5%. Only 13 players his age walked less, and only 6 struck out less. It is hard to say if this means anything, or if it is good or bad.
Rivas had the best wRC+ (not park adjusted, but I think complex park is neutral). Still his wRC+ was only 87, and that was with little power (.051 ISO). Heredia and Burns had ISOs under .100 as well. Baez's ISO was .145, 26th best at his age. Low BABIPs contributed to keeping Heredia, Burns, and Baez to low batting averages. Baez's BABIP was .208, a surprise given his speed and power. The catchers were in the .270s.
Overall, these guys did ok. They didn't excel with the bats, but they mostly survived. Baez turned 18 on 6/28, so he had to be one of the 10 youngest players. Heredia was almost a year older. Burns and Rivas were born in Feb/Mar. It is hard to say anything about the catchers. Baez is a big prospect, even if he struggled in the complex. I find Rivas exciting. His low k-rate at SS appeals to me. Hopefully he can play A ball next year and do well.