Here is Michael Silverman of the Boston Herald:
John Lackey will make a rehab start with Portland (AA) tomorrow — four innings, about 65 pitches — that could, barring a setback, be the one and only rehab start he would need before being re-activated from the DL with his right biceps strain. He would be on track to pitch for the Red Sox next Saturday, April 27, against Houston.
Lackey suffered that right biceps strain in his first start of the 2013 regular season. It initially looked like a pretty serious injury, but the 34-year-old may only wind up missing a little more than three weeks.
Lackey is owed a $15.25 million salary this year and another $15.25 million in 2014. He has a rough 5.24 ERA, 1.50 WHIP and 6.5 K/9 in 379 1/3 innings since signing an $82.5 million deal with Boston.