As we learned on Monday night, John Danks has a mild Grade 1 subscapularis strain. Team doctor Greg Nicholson said there was no tendon or ligament damage, and the labrum is intact. Trainer Herm Schneider said Danks will start a rehab and strengthening program on Friday.

I read all this, and my immediate thought was, “What is a subscapularis tear?” I knew it had something to do with the shoulder, but that’s about it. So I went out and did some research to better explain what Danks’ issue is.

The subscapularis muscle is part of the rotator cuff. It’s the larger muscle at the front of your shoulder. It’s also the strongest muscle in your shoulder. According to ShoulderDoc.co.uk, it’s the muscle that is essential for throwing.

A subscapularis tear is less common than other tears that are simply called rotator cuff tears. It is a more painful tear than a regular rotator cuff tear because the subscapularis tendon is attached to (or wrapped around…I can’t tell based on this picture I’m looking at) the long head biceps tendon (LHB). Often when the subscapulis tendon is torn, the LHB is torn and dislocated, causing more pain.

A subscapularis strain is obviously not as bad as a tear, but because the subscapularis tendon is responsible for throwing, that is why Danks is having pain when he pitches. Because it is a strain rather than a tear, Danks will not need surgery, which is a good thing. Since the subscapularis tear is not as common as other rotator cuff tears, many surgeons are unfamiliar with the surgical procedure.

Danks has a strain, so it seems that rest, rehab and strengthening is the best course of action. His strength training will start on Friday under Schneider’s supervision, and in three to four weeks, he will start another minor league rehab assignment.

Now that Danks’ injury has been diagnosed, hopefully he will rehab well and come back better than his previous starts this season. For now, the pitching staff has to step up. Jake Peavy and Chris Sale have stepped up for the most part, but they also have some injury history. I am particularly concerned about Sale since he throws with the inverted W motion. If he and Schneider take care of his arm, he should be OK.

Jose Quintana has been a surprise to me since coming up when Danks went on the DL. He has shown that he can pitch and do it relatively well. He is still a new-to-the-Majors pitcher, so I do expect some bumps, but with the guidance of his coaches and teammates, he should be just fine.

The problem pitchers that really need to step up are Gavin Floyd and Philip Humber. Floyd is consistently inconsistent. He has great games, and then he has awful games. That kind of play is not going to help the White Sox win the AL Central this season, especially since Quintana is basically unproven. Floyd also has to remember that this year is the end of his contract. He has a club option for 2013, but if he keeps playing so inconsistently, the club may not pick up that $9.5 million option.

Humber has been up and down. He has had so many awful performances after that perfect game that it makes me sad every five days. The problem with Humber is that I don’t really know what to do with him. Do the Sox put him in the bullpen? If he’s in the ‘pen, do they put someone like Zach Stewart in the rotation or do they send down a bullpen guy and call up someone like Dylan Axelrod to put in the rotation?

The Sox have some decisions to make if the pitching keeps faltering. Until then, all Sox fans can do is hope things shape up and wish Danks a speedy recovery.