Rash is a poster child for how Major League Baseball's new collective bargaining agreement is already starting to impact the college game.
With new limitations on how much teams can spend on prep stars, it appears more will be heading to college instead of the minor leagues.
In November 2011, the CBA capped the amount of money each organization could spend in the first 10 rounds of the draft. In the first draft under the new rules, the number of high school players rated among Baseball America's top 200 draft-eligible prospects went unsigned or undrafted increased slightly to 35, up from 26 in the 2011 draft.
Of those 35 unsigned or undrafted players, 33 are now playing Division I college baseball. The numbers might increase after the 2013 draft in June.
"It's already had an impact," Vanderbilt coach Tim Corbin said of the CBA. "What you're seeing is the kids who are drafted from round five or after, I think you're seeing more of those kids show up in school."
Rash, the highest-drafted high school player not to sign a pro contract last year, said the Phillies didn't offer the $750,000 signing bonus he sought. He was the 95th overall selection, and the slot value for that spot was $500,000. Rash enrolled at Missouri instead and is 2-1 with a 3.43 ERA and 19 strikeouts in 21 innings.
He said he probably would have turned pro directly out of high school under the old agreement.
The cap "really makes it difficult for teams to be able to just go out and throw money at someone," Rash said. "They have to play more of a game with it. They have to really be smart with their money. Before the new CBA, they could just throw money at someone and make that decision for them."
LSU shortstop Alex Bregman is another player tearing up college fields and not the minors.
He was considered a potential first-round draft pick before breaking a finger his senior year at Albuquerque (N.M.) Academy. After getting picked by the Boston Red Sox in the 29th round, Bregman went to LSU and is batting .444 with 41 runs scored and 35 RBIs in 34 games.
The Tigers (32-2) are off to the best start in school history, thanks in part to Bregman's presence.
"I think in the old rules, they probably would have still taken a flyer on him maybe not in the first round but they would have watched him all summer and then they would have had a chance to give him a couple of million dollars in August before school started, and he probably would have signed," LSU coach Paul Mainieri said. "Because of the new rules, he ends up coming to school, where he's been leading our team."
Tennessee has played 17 true freshmen this season, the most of any Division I team. The list of Tennessee freshmen includes shortstop A.J. Simcox and outfielder Vincent Jackson, who were rated by Baseball America among the nation's top 200 draft-eligible prospects last year.
Before MLB's latest collective bargaining agreement, teams could offer an unlimited amount of money to players they drafted.
Now MLB assigns a slot value to every pick in each year's draft which in 2012 ranged from $7.2 million for the No. 1 overall pick to $125,000 at the end of the 10th round. A team's total allotment is the sum of the slot value of all of its selections in the first 10 rounds.
A team can spend its allotment as it sees fit, going above or under slot value for an individual pick if it desires. But if a team goes above the overall threshold, it must pay a luxury tax. Any players selected after the 10th round of the draft can be signed for up to $100,000 without counting toward a team's cap.
Miami Marlins scouting director Stan Meek said the draft's rule changes are more restrictive, but can be a positive for pro organizations because it streamlines the negotiating process.
"It makes for a more honest discussion and it certainly makes us do our homework with prospects," Meek said. "We have to get a good understanding of how much it's going to take for a player to sign because we don't have as much wiggle room. It's brought a little more realism to everything."
Meek said he expects the new rules will help the college game because good prospects who aren't considered elite ones that might be slotted from the sixth to 10th round would be more likely to go to school because the hope for a large signing bonus isn't as feasible.
Major League Baseball's slot value for a sixth-round pick in the 2012 draft ranged from about $200,000 to $250,000. That's not necessarily an enticing amount for a player who has a scholarship on the table and could potentially improve his draft position after a good college career.
Still, LSU's Mainieri pointed out the rules also can work to college baseball's detriment.
Mainieri signed outfielder Hayden Jennings last year and didn't expect him to get drafted in the first 20 rounds. Jennings instead went to the Washington Nationals in the sixth round and never played for LSU. Mainieri said Jennings signed with the Nationals for $100,000, well below slot value.
"Basically what was happening was Washington was drafting a player they knew they could sign for under slot to save them money they could probably put into one of their higher picks," Mainieri said. "We ended up losing a player there that we did not expect to lose. It happens in both directions."