After suffering a right forearm strain in July Pirates closer Jason Grilli vowed to make it back before the end of the season. And he’s well on his way to meeting that goal.

According to Tom Singer of MLB.com Grilli will begin a minor league rehab assignment with Double-A Altoona today and throw around 20 pitches. He’s expected to make another appearance on Monday before moving up Triple-A Indianapolis on Wednesday. He could be cleared to return after that if all goes well.