Jake Arrieta Out 7-10 Days With Grade 1 Hamstring Strain

9:25pm: Arrieta told reporters after tonight’s game that the MRI revealed a Grade 1 strain of his right hamstring (video link via ESPN Chicago’s Jesse Rogers). The right-hander will miss at least one start and possibly two with the ailment, but it doesn’t sound as if there’s any long-term risk.

Sept. 5, 7:00pm: Arrieta is very likely to miss his next start, per MLB.com’s Carrie Muskat, but there has yet to be any indication that he’ll require a lengthy absence from the mound. Arrieta underwent an MRI today, though the results from the test aren’t yet known. Arrieta said before tonight’s game that it was likely a cramp that caused him to exit.

Sept. 4, 6:33pm: For now, at least, it seems Arrieta may have dodged a significant injury. He thinks he may even be able to take his next start, Gonzales tweets, and might not even need an MRI.

4:35pm: There’s still no diagnosis, but Arrieta is receiving treatment to his right hamstring, the team announced (via Mark Gonzales of the Chicago Tribune, on Twitter).

4:26pm: Cubs righty Jake Arrieta was pulled from his outing today in the third inning after seemingly suffering an injury to his right leg. He tried to throw a warm-up pitch after the issue arose, but was not able to carry on.

Needless to say, there’s no way of knowing at this point whether there’s any reason for long-term concern. The Cubs have only announced what was obvious to the naked eye: Arrieta left with “an apparent right leg injury.”

But at this stage of the season, even relatively minor injuries can be quite important. Arrieta, the National League’s Pitcher of the Month for August, is expected to help lead the rotation down the stretch and into the postseason.

Despite some iffy moments earlier this year, Arrieta currently owns a 3.36 ERA over 158 innings, with 153 strikeouts and 52 walks. That overall body of work — and his track record of durability — had also seemingly set him up for quite a lucrative foray into free agency at season’s end.

At this point, there’s not much the Cubs or Arrieta can do but wait and hope for the best. No matter the severity of the injury, the team can’t add an outside pitcher and utilize him the postseason; the deadline for doing so was August 31st.

While Chicago could in theory still acquire a starter just to help out during the month of September, there’s no real reason to do so. The Cubs had six quality options for the rotation, so won’t need to worry about depth.