Rats, given how much time he missed, Reyes is unlikely to start for St. Louis to open this season. Since this discussion is about candidates to replace Mikolas to start the year if needed, Reyes is an unlikely choice.
Most reasonable best case is that Reyes earns a pen spot or if he doesn’t make the team, he will be back in Memphis to sharpen up.
Many people are keeping expectations low for Reyes after three years of disappointment. If he can turn the corner, though, he will certainly earn a prominent role. If.