And he came through, smashing a ball down the left-field line to bring Balentien home and give the Mariners a 4-3 win in front of 30,758.
As for Matsuzaka, the Red Sox were identifying his problem as right shoulder fatigue.
"He felt some, I guess, fatigue is the right word," manager Terry Francona said. "We're not going to run somebody out there when we think [there's something wrong]. It's too long of a season. I don't think he really wanted to give the ball up."
Matsuzaka was examined by med ical personnel, and will be further examined today.
"Even before I went up on the mound, I felt that things were a little bit off in the bullpen," Matsuzaka said, through interpreter Masa Hoshino. "I wouldn't go so far as to call it discomfort, but I wasn't at my best even before going into the game.
"After pitching the third inning, I definitely felt that there was something wrong. At that point, I had a conversation with the coaching staff."
"We knew in between innings," Francona said. "I knew that we wanted to keep an eye on him."
Both Francona and Matsuzaka said they did not know if the pitcher would be able to make his next start.
As Matsuzaka worked to get ready for the bottom of the fifth inning, he put a hand to his back after the second warm-up. Catcher Kevin Cash jogged out to the mound to meet him, with Francona and the training staff following quickly. It was not long before Matsuzaka was walking off the field just 65 pitches (and no walks) into his outing.
Though the specter of Suzuki in the batter's box wasn't a likely contributor, it couldn't have helped. Suzuki had already hit a double and a single, and the Mariners were ahead, 3-0. David Aardsma relieved Matsuzaka, leaving five innings for the bullpen to fill.
That wasn't the only early exit for the Red Sox. Both Julio Lugo and Francona were ejected just three batters later. After Aardsma had gotten two outs and walked Jose Vidro, Lugo apparently started bugging third base umpire Angel Hernandez about a checked swing he had called on a 1-and-0 pitch to Raul Ibanez.