NEW YORK -- Highly touted pitcher Mark Appel spurned the Pittsburgh Pirates and decided to remain at Stanford for his senior season, the first big casualty of baseball's new restrictions on amateur signing bonuses.

Appel was the only unsigned player among 31 first-round picks, turning down an offer of $3.8 million from the Pirates.

Mark Appel was the only unsigned player among 31 first-round picks, turning down a $3.8 million offer from the Pirates. Larry Goren/Four Seam Images/AP Images

Projected by some to be the No. 1 selection, some teams shied away from the right-hander because of the expected demands of his adviser, Scott Boras. Appel was selected eighth by the Pirates.

That slot was assigned $2.9 million from the drafting team's bonus pool in baseball's new labor contract, which imposes penalties on clubs that exceed the threshold -- the totals of the slots for a team's selections in the first 10 rounds.

Pittsburgh was prepared to go as much as 5 percent above its threshold and incur the first level of penalty, a 75 percent tax on the overage. But the Pirates didn't want to fall into higher levels, which include the loss of future draft picks.

"After much thought, prayer and analysis of both opportunities, I came to the conclusion the best decision is to remain at Stanford continuing my studies, finishing my degree, and doing all I can to assist the Cardinal baseball team in our goal to win a national championship," Appel said in a statement. "I greatly valued the prospect of a professional opportunity and I will pursue a professional baseball career after getting my Stanford degree."

Appel, who turns 21 on Sunday, also failed to sign in 2009, when Detroit selected him in the 15th round with the 450th pick after his final season with Monte Vista High in San Ramon, Calif. Appel will go back into next year's draft.

Under the labor deal, agreed to in November, the deadline for draft picks to sign was 5 p.m. Friday, a month earlier than under the previous collective bargaining agreement.

Trying to end a record streak of 19 consecutive losing seasons, the resurgent Pirates began Friday with a one-game lead in the NL Central.