Clearly, Matsuzaka was hampered by a neck injury which prevented him from making a side session between starts. It is the same injury -- to the trap muscle on the right side -- that caused him discomfort during Spring Training and in late May, when he was on his Minor League rehab assignment.
Matsuzaka has made just five starts since coming back from Tommy John ligament transfer surgery, going 0-3 with a 6.65 ERA.
"Daisuke, that neck thing, we're going to try to give it some more time and see if it goes away for good this time," said manager Bobby Valentine.
To replace Matsuzaka on the roster, the Red Sox recalled corner infielder Mauro Gomez from Triple-A Pawtucket. Gomez, who had one short stint with Boston earlier this season, is having a monster year at Triple-A Pawtucket, hitting .311 with 19 homers, 55 RBIs and a .980 OPS.
"Mauro has been swinging the bat well," said Valentine. "We'll see if he can be there if we need him."
Gomez was on Boston's roster from May 11-20, but he had just two at-bats.
It remains to be seen if Gomez will do anything more than pinch-hit during Boston's West Coast road trip. His main position is first base, where the Red Sox already have Adrian Gonzalez.
Third base is where there's a current opening, with Will Middlebrooks day to day with left hamstring soreness. Gomez does have some experience at third, but he hasn't played there since 2009. In 71 Minor League games at the hot corner, Gomez made 31 errors.
"He plays third, we think," said Valentine. "We're going to find out. He signed as a third baseman. He played a lot of third base growing up and has been taking third-base grounders all year."