Triston Casas is getting closer to a return to the Red Sox after missing time with a rib injury. The slugging first baseman has eight hits, including five doubles, in eight games with the Worcester Red Sox on a rehab assignment. Gene J.

Puskar/Associated Press Triston Casas is working his way back to the Red Sox. It won’t be this week, but it will be soon. The 20-day limit on his injury rehab assignment means he would have to return Aug.

19. The first baseman has played eight games with the Triple-A Worcester Red Sox as he returns from the rib cartilage injury he suffered on April 20. He’s hit the ball well, with five doubles, yet he’s not quite ready to return.

“He feels he still needs more,” Red Sox Manager Alex Cora said Sunday. “We’ll keep getting him at-bats. He feels close to 100 percent in a sense.

One hundred percent for him is kind of like how he bounces back the next day. How he bounces back from batting practice and all that stuff. “He’s still going to be down there.

Most likely next week he’ll stay there and then we’ll see what happens.” The Red Sox have the luxury of being patient with Casas thanks to Dominic Smith. From June 29 through Sunday’s loss to the Astros, Smith is hitting .

267 with 12 doubles and three homers. He has also been a steady defender at first base. Smith, a first-round pick of the Mets in 2013, has gone back to the fluid swing that made him one of the best hitting prospects in his draft class.

He has worked with hitt.