BALTIMORE — Boston Red Sox right-hander Clay Buchholz, who has been on the 15-day disabled list since June 19 with a lower back strain, is scheduled to have his first throwing session off a mound Friday.

Buchholz was 6-3 with a 3.48 ERA before being sidelined. He has been throwing off flat ground and gradually increased his workout totals from 60 to 120 pitches this week.

Manager Terry Francona said the pitcher’s most recent stint went well, and the team will use this week’s session to determine the next course of action. If the mound work goes well, the Red Sox likely would send Buchholz on a rehab assignment.

Buchholz, who has made 14 starts, said Tuesday his back feels better. He says arm strength is not an issue, but he needs to regain strength in his lower body.