The excitement of one day throwing a pitch in a Houston Astros uniform might be starting to fade for Brady Aiken.

Selected first overall last month in MLB’s first-year player draft, the left-handed pitcher from Cathedral Catholic High School in San Diego, Calif., and his adviser Casey Close are embroiled in a contract dispute with Astros general manager Jeff Luhnow.

Soon after the draft, it appeared the two sides had agreed to a $6.5 million US bonus, $1.4 million less than the $7.9 million allotted for the No. 1 overall pick. But after Aiken’s physical, the Astros reduced their offer to $5 million, according to CBSSports.com, which reported the pitcher has an elbow ligament issue.

Thing is, Aiken was said to have reached 98 miles per hour and showed no signs of discomfort during his final start of the season, a May 30 playoff contest when he struck out 14 in six innings.

Houston, Close said, made Aiken a revised offer of $3,168,840 million, or the minimum amount required to ensure the Astros get the second overall pick in next year’s draft as compensation if they failed to sign Aiken.

It’s believed the money Houston is trying to save on Aiken is almost the amount it needs to sign two other high school pitchers: fifth-round draft pick Jacob Nix, who is also advised by Close, and 21st-rounder Mac Marshall.

The story is gaining traction because the deadline to sign draft choices is Friday at 5 p.m. ET.

Two years ago, the Astros picked high school shortstop Carlos Correa first overall and signed him to a $4.8 million bonus when the pick was slotted for $7.2 million. Houston used the money it saved to exceed slot with a $2.5 million bonus to high school right-hander Lance McCullers Jr.

So, is Aiken healthy like his camp contends, and Houston is simply using a medical concern to pressure the young pitcher to accept a lower bonus? Or, do the Astros have medical reports suggesting otherwise?

“Throughout this process, we have been in touch with MLB to ensure that we are adhering to the rules at every point and we are confident that this has been the case,” Luhnow told FOXSports.com.

Beyond that, the GM isn’t saying much, a much different tune from early June when he raved about Aiken, a six-foot-three, 210-pound southpaw the Astros scouted for three years. He struck out 111 of the 228 batters he faced as a senior, and had a 7-0 record and 1.06 earned-run average in 59 2/3 innings.

Aiken is good, real good, a remarkably advanced pitcher who throws a four-seam and two-seam fastball and increased his fastball velocity from 92 to 97 mph this season. His repertoire also includes a curveball and changeup.

But former major leaguer Tony Clark, the head of the players’ union, believes the Astros have manipulated baseball’s rules in an attempt to save money.

“You can rest assured that the manipulation that we think happened in this case is going to lead us to have some conversations that are going to make sure that players received the support that they deserve,” Clark told reporters before Tuesday night’s all-star game in Minnesota.

Aiken and Nix have committed to UCLA if they don’t sign with Houston, while Marshall appears to have started immersing himself in college life at Louisiana State University, making it potentially difficult to sign him now.

In a few days, we’ll know if the Astros strike out on none, one, two or all three of them.