Denver players celebrate following their 13-10 win over Villanova during their NCAA Tournament first round lacrosse match up at Denver University. (AAron Ontiveroz/AP)

The NCAA men’s lacrosse championship weekend, the sport’s showcase event, arrives at M&T Bank Stadium in Baltimore on Saturday following a week not of hype but of milestones.

Last Saturday, Denver became the first team west of the Mississippi River to reach the semifinals; on Tuesday, Michigan formally announced it was adding Division I men’s and women’s lacrosse teams; and on Thursday, the Division I all-American first team included Cornell junior Roy Lang, a native of San Francisco, not a city typically associated with lacrosse prowess.

The events are instructive to the pace and growth of the sport well beyond its East Coast roots. But they are not the only signs.

The four teams that reached the NCAA semifinals 20 years ago were made up of players from nine states; 89 percent of them were from Maryland and New York. This weekend, the four semifinalists — Denver (15-2), Virginia (11-5), Maryland (12-4) and Duke (14-5) — have players from 24 states; 35 percent are from New York and Maryland.

Among the starters on Saturday, when Virginia plays Denver and Maryland faces off against Duke, will be players from California, Colorado, Florida, Kentucky, Minnesota, North Carolina, Ohio, Texas and Washington state.

“College coaches are showing the highest level of interest in players out West, more than ever before,” said Peter Worstell, a Long Island native who starred for Maryland in the late 1970s and now is head coach at San Ramon Valley High outside Oakland.

Worstell founded the “California Gold” showcase tournament in 2008. It already has become an important stopping off point on the summer recruiting circuit for Division I coaches.

“This didn’t just happen,” he said. “There is a reason I didn’t start California Gold earlier. I didn’t feel there was enough talent. But the level of play has exploded. . . . What is happening out here is very, very real.”

Seniors on Worstell’s San Ramon Valley team will play next year for Navy, North Carolina, Penn State and Syracuse.

The recruiting trend stems from the explosion in the number of young people playing the game. The number of boys’ high school varsity teams has increased 55 percent the last five years, according to the National Federation of State High School Associations. Nearly 325,000 boys 15 and younger were playing the game in 2010, a 9.2 percent increase from 2009, according to U.S. Lacrosse.

Yet, the number of roster spots on men’s Division I programs has been slow to keep pace. The number of schools with men’s teams declined to 54 in the mid-2000s after Michigan State and Boston College dropped the sport, largely over compliance with Title IX, which requires that colleges and universities have equal opportunities and scholarships for men’s and women’s athletes. Butler, which has since made a name for itself as a national basketball power, dropped lacrosse in January 2007.

The number of men’s programs, however, has recently begun to increase again. Jacksonville added men’s and women’s teams for the 2010 season; it is the first men’s Division I program in Florida.

This spring, 61 schools fielded Division I teams. Michigan this week became the most recent school to add lacrosse. Marquette announced last December it was adding the sport for the spring of 2013. High Point (N.C.) also is adding lacrosse for 2013.

Lacrosse is the first sport Michigan has added in around a decade, Athletic Director David Brandon said in a news conference Tuesday.

“It clearly is the fastest growing sport in Michigan at the high school level,” Brandon said. “It’s a great spectator sport, it’s fast . . . it’s also a great television sport. The interest of this sport at the youth level is phenomenal.”

Coaches and administrators around college lacrosse welcomed the new programs.

“I hope Michigan does extremely well,” Maryland Coach John Tillman said this week, “so every other athletic director says, ‘Wow, we can get really good students here, lacrosse gives us great exposure, the young men can represent us in the best possible way and it’s not going to cost $40 million to be competitive.’ ”

Michigan’s entry into college lacrosse comes at a time when the sport’s East Coast-based boundaries are dissolving. Notre Dame made the NCAA title game last year, losing in overtime to Duke. Ohio State and Notre Dame reached the quarterfinals in 2008.

Denver’s profile took a huge leap forward when it hired Bill Tierney from Princeton in the summer of 2009. Tierney won six national titles at Princeton. He landed the Pioneers in the Final Four in his second season; Princeton reached the Final Four in his fifth.

“We’re still under the radar I think, although maybe a little less after this year, with kids growing up and saying, ‘I want to go to Denver,’  ” Tierney said. “We’re not on the tips of tongues yet of 10-year-olds, but if you look at our roster you can see we’ve gotten great ones from a lot of different places.”

Denver’s roster on Saturday will feature players from 18 states, plus Canada. Among the states not represented: New York, whose high schools’ stars have for decades fueled the top college teams in the country.

“When we beat Duke on Long Island [on April 9] a lot of the press was saying, ‘Well, now this will help your recruiting,’ ” Tierney said. “I was like, ‘Wait a minute. We just beat the defending national champions with nobody from Long Island.’ ”

Cornell’s Lang is not likely to be the last all-American from California. Virginia freshman Rob Emery went to the same high school as Lang — St. Ignatius — and moved into Virginia’s starting lineup late this season.

“I’ve been saying for years and years that as the game has grown, we’re getting more athletic kids from these other areas, the Midwest and the West,” Virginia Coach Dom Starsia said. “But that the skilled kids basically were still the East Coast kids.

“Rob Emery is someone who begins to sort of change that paradigm a little bit. He is an athletic kid with wonderful skills. . . . Ten years ago we probably wouldn’t have imagined that it was possible, but I think with the teams that are involved now and the rosters of all these teams — there are just kids from everywhere now. It’s the clearest sign the game is growing.”

The question being asked within lacrosse circles is: Where will the sport be in five years?

Maryland junior Jake Bernhardt, a starting midfielder, said lacrosse is “growing like wildfire” in his home town of Orlando. Added his brother Jesse, a sophomore longstick midfielder for Maryland: “I don’t see it decreasing.”

But the sport does need capable coaches, something the brothers said is lacking.

“There’s a big difference between the amount of players in Florida and the amount of coaches in Florida,” Jake Bernhardt said. “There aren’t as many coaches who know the sport well, and it’s hard for them to keep up with the players.”

Tierney said his biggest challenge upon arriving in Denver was to get players from different backgrounds to blend as a team.

“The biggest challenge came getting them all together, not physically but emotionally and mentally,” he said. “To believe in us that we had their best interest at heart. . . . And it’s taken a while, but it shows that kids are kids. If they want to play lacrosse and work hard in school, it doesn’t really matter where they’re from.”