For athletes, the big decision is whether they depart on missions directly out of high school, or play a year and then go, and those who spoke to The Salt Lake Tribune are ecstatic to now have that choice.
For coaches, the question is whether the changes are good for their programs, and whether they are more or less apt to recruit athletes who will be going on missions.
Returned missionaries make up about one-third of Utah football coach Kyle Whittingham's roster, so he, too, was taken aback for a moment before realizing the change will have a drastic, yet "positive impact" on his program.
"In the past, we were juggling when to send athletes out, determining when they were 19 and whether they should play a season or stay [home] a whole year or go right away," Whittingham said. "This should lay some common ground."
Obviously, most coaches around the country are not nearly as familiar with recruiting mission-bound athletes as Mendenhall, Whittingham and Utah State's Gary Andersen. However, Stanford coach David Shaw and Cal coach Jeff Tedford both said Tuesday that the change would not affect their recruitment of LDS players, but would mean the players likely will serve missions before enrolling as opposed to playing a year.
"It doesn't impact us whatsoever," Shaw said. "... Whether they go on a mission early or go later, if it is the right guy for us, we'd definitely still recruit him."
Tedford, who was unaware of the change, said it would not have much effect, other than "they would just leave earlier." He said Cal would recruit LDS players "with the understanding that [their mission service] was going to happen right away."
Obviously, the impact reaches far beyond football.
Utah basketball coach Larry Krystkowiak, for instance, said the change will help his program, which traditionally has included several returned or prospective missionaries.
"Everyone can go right away now," he said. "We don't have to wait until [they are] 19 anymore. It's just more flexibility for all parties now."
When he took the job in 2008, USU's Andersen promised to recruit more mission-bound athletes than his predecessors, and he's done just that in reviving the program. He said the change is "a great thing for the program. It offers more flexibility and it can only help down the future. This is a good thing for everyone involved."
For BYU's Mendenhall, whose program currently has 38 missionaries serving in 17 different countries and whose current roster is composed of approximately 70 percent returned missionaries, the change will bring some major reshuffling, but the coach said he likes it.
"It gives them a chance to have a clean start, right from high school, to go out on a mission, and then uninterrupted play when they come back, if they are ready and they want to. So it will just take us a while to get to that point organizationally, but we support the decision 100 percent. Now it is our job to make it all work in relation to football," Mendenhall said.
Female athletes who are LDS and coaches of women's sports are affected as well, because the minimum age for young women to serve missions was lowered from 21 to 19. Before, women athletes went on missions after their college careers were over, rather than interrupt them when they had just one year of eligibility remaining.
Certainly, the minimum age change will have a great impact on the athletes themselves, and many already have started preparing differently.
For instance, Lone Peak High senior basketball star Nick Emery, who has committed to BYU, originally was going to leave on a mission next fall, when he turns 19.
"My plans [now] are to leave right after graduation and come back and have 4 straight years!" Emery noted on his Twitter account.
Another Lone Peak basketball player who has committed to BYU, Eric Mika, tweeted out: "Still don't know what to think or say right now. … [I am] frozen solid, but my head is spinning. Turn 18 in 4 months."
BYU quarterback Riley Nelson, who played a season at Utah State before a church mission to Spain, said he would have gone first, and several other BYU football players, including cornerback Preston Hadley, echoed Nelson's sentiments Monday.
"I turned 18 a week after I graduated [from high school]," Nelson said. "I think that would have been nice timing [to go]. Then you get back as a 20-year-old kid, and I probably would have redshirted, which would have been nice. … I don't know what impact that will have, but I think it is good getting them out at 18 and getting them back at 20, and then having five [years] to play four."
And don't forget about the impact the change potentially could have on the top high school basketball player in the country, Jabari Parker, who happens to be LDS and has mentioned the possibility of serving a mission.
He turns 18 next March, and now could go on a mission before enrolling at one of his listed five favorites: BYU, Florida, Duke, Michigan State or Stanford.
Before the change, he would have had to play a year first.
"When he's 18 and if he did want to go on a mission, he can now," Parker's father, Sonny Parker, told Scott Powers of ESPNChicago.com. "He has to decide whether or not [he will]. He hasn't decided one way or another."
Tribune reporters Kurt Kragthorpe, Lya Wodraska and Tony Jones contributed to this report.
LDS missionaries on Utah's big three football rosters:
RMs on Currently
School roster serving
BYU 77 38
Utah 25 18
Utah State 17 N/A