At Citizens Bank Park, people are praying. And not just for wins. They’re also praying that the Phillies, one of the few Major League Baseball teams that has not reached 85% vaccination among critical players and staff, don’t have too many stars test positive for COVID-19. Manager Joe Girardi offered up this prayer for the Phillies faithful: “You just pray that they’re either a false positive or the guys that are nearby don’t get it. That’s your prayer.” We’d suggest that vaccines — a “miracle” of science — are better than prayers at preventing the spread of COVID-19.

Employers typically enjoy significant flexibility to mandate vaccination, so long as they offer medical and religious exemptions. This is likely true even for vaccines available only under emergency use authorization. But things get a bit more complicated for unionized workers, for whom vaccine mandates would count as a condition of employment that must be collectively bargained. That means MLB and the Players Association would need to come to an agreement before any mandate could be imposed. But this shouldn’t be the typical adversarial negotiation — given what’s on the line, this should be a home run.

Before vaccine mandates are imposed, it’s ethically desirable to allow for a time-limited period of voluntary uptake. During this time, people should have easy access to vaccines, be given information about the importance of vaccination, and have any lingering concerns addressed. But if vaccine uptake remains insufficient and the pandemic persists as a public health issue, mandates are a reasonable response. We think the Phillies — and MLB — have reached that point.

» READ MORE: As Citizens Bank Park fully reopens to fans, the Phillies haven’t met MLB’s COVID-19 vaccination threshold | Scott Lauber

To date, MLB has encouraged vaccination by offering soft incentives. Vaccinated players and personnel are subject to fewer restrictions than those who remain unvaccinated: They can take off their masks in certain settings, reduce their frequency of COVID-19 testing, and have family members join them on the road. Once a team reaches 85% vaccination, further group restrictions are removed. For example, “shared amenities like video-game systems and pool tables will once again be permitted in the clubhouse.” If these group benefits were even stronger, and if these inconveniences made a bit more painful, teams might be able to take advantage of further peer pressure to increase vaccine uptake. But even as things stand, more than two-thirds of MLB teams have reached the 85% vaccination threshold. There’s no reason to cheer the Phillies for falling short on this important statistic.

In team sports, people need to be team players. This means getting vaccinated. Players like Alec Bohm who test positive for COVID-19 need to sit out for a minimum of 10 days. Unvaccinated players who come in contact with them are also sidelined, leading to a competitive disadvantage for the Phillies and disappointing fans. More broadly, forgoing vaccination makes the workplace less safe for people who can’t be vaccinated or for whom vaccines are less effective. Additionally, unvaccinated players could facilitate viral spread off the field and, as they travel to games, beyond Philadelphia. This is particularly concerning as variants, which can make the virus that causes COVID-19 spread more easily or become resistant to vaccines, spread in the population.

» READ MORE: Phillies’ Joe Girardi doubts Sunday’s COVID-19 episode will prompt more players to get vaccinated

Whether they aspire to be or not, professional athletes are role models. As role models, they would ideally use their platform to encourage vaccination. Teams have in fact sought to do just that. As part of MLB’s broader “Vaccinate at the Plate” effort, the Phillies recently partnered with Penn Medicine to offer attendees at select games the one-dose Johnson & Johnson vaccine. Fans who received their vaccine at the ballpark were also offered free tickets, giveaway items, and hot dogs. Yet fans might wonder why they should get vaccinated if their favorite players haven’t been.

In the broad sweep of the pandemic, it’s easy to think there’s no reason to be “phanatical” about whether a few Phillies forgo vaccination. But especially as professional sports seek to lure fans back to the stands, and as vaccination rates wane, every added bit of support can help. Sports leagues, players’ unions, and teams should step up to the plate, mandating comprehensive vaccination against COVID-19.

Emily A. Largent and Holly Fernandez Lynch are senior fellows at the Leonard Davis Institute of Health Economics and assistant professors of medical ethics and health policy at the Perelman School of Medicine at the University of Pennsylvania.