He is just 19, but when Felix Hernandez stands on the mound, he looks anything but a teenager.

The 6-foot-3 right-hander throws a 97-mph fastball, and his biting curve mystifies batters as it tumbles through the strike zone.

After less than three seasons of professional ball, Hernandez is ready to show off his stuff to major league hitters. The phenom will make his major league debut today when the Mariners close out a three-game series in Detroit.

"Felix is Felix," said Tacoma Rainiers catcher Ryan Christianson. "When he's good he's good, and when he's bad, he's good."

Hernandez comes to the Mariners after dominating the Pacific Coast League while pitching at Class AAA Tacoma. Hernandez was 9-4 with a league-leading 2.25 ERA and 100 strikeouts in just 88 innings pitched. The numbers are eye-popping for any prospect, let alone the youngest player in all of baseball above Class A.

"He's a very, very talented young man," Tacoma Manager Dan Rohn said. "He has a lot of gifts others don't have."

* RED SOX' RAMIREZ LEAVES GAME: Manny Ramirez bruised the right side of his chest and face and was day-to-day after colliding with SS Edgar Renteria while both chased a short fly ball in left field last night.

Renteria stayed in the game. Ramirez was replaced in left field by Gabe Kapler when the Royals came to bat in the third.

Ramirez caught Ruben Gotay's fly in the top of the second inning and held the ball as the fielders fell. The left fielder hit his AL-leading 30th homer, a three-run shot, in the first, raising his major league-high total to 100 RBI.

After catching the ball while reaching down, Ramirez collided with Renteria, who was running out with his back to home plate. Renteria's left arm hit Ramirez in the face, and their shoulders appeared to hit each other as Renteria's glove fell off.

* A. BOONE GETS NEW DEAL: The Indians restructured 3B Aaron Boone's contract for 2006 and exercised their option on it. The new deal also includes a mutual option for 2007.

After missing all of 2004 while recovering from two surgeries on his left knee, Boone batted only .123 in April. He followed that up with a .188 average in May. But in 47 games since June 1, Boone is hitting .298 with six homers and 23 RBI.

-- From News Services

Boston's Edgar Renteria, left, collides with Manny Ramirez while chasing a fly ball. Ramirez left the game afterward.