Reds rookie sensation Jay Bruce, right, is greeted by third base coach Mark Berry after hitting a first-inning homer off Justin Masterson last night.

AP / Tony Tribble

CINCINNATI — As reported first in The Journal two days ago, Daisuke Matsuzaka will be throwing a rehab assignment for the Pawtucket Red Sox on Monday night in Lehigh Valley against the Iron Pigs.

Manager Terry Francona made the announcement yesterday afternoon as Dice-K threw a side session in the indoor cage, unable to throw outside on a mound because of rain.

Francona said Matsuzaka will throw 70 to 80 pitches for the PawSox. If all goes well in that outing, Matsuzaka will start for Boston next Saturday at home against St. Louis.

Matsuzaka hasn’t pitched in a game since leaving his May 27 start in Seattle after four innings because of a slight strain of his right rotator cuff. His record is 8-0 and he has a 2.53 earned-run average.

“Instead of worrying about whether it is the major leagues or the minor leagues, I’m just going to approach the game (Monday night) as I regularly would,” Matsuzaka said after throwing yesterday.

“It was a good and useful break. The big thing was [that] it gave me a chance at this time of year to rest my body. Not just my body, but my shoulder and elbow,” he said.