Cubs' Chris Bosio: 'Got To Be Smart' About Jake Arrieta's Return Timeline

(CBS) Prior to his team's win against the Mets on Tuesday evening, Cubs manager Joe Maddon all but ruled right-hander Jake Arrieta out at least through this weekend's series against the Cardinals.

So when will Arrieta return from his strained right hamstring? Pitching coach Chris Bosio wants it to be as soon as possible, but with every game carrying so much meaning and the risk for re-injury so clear with a hamstring, the Cubs know they need to reinsert Arrieta into the rotation in his top form.

Arrieta hasn't pitched since leaving in the third inning of his Sept. 4 start at Pittsburgh. He threw off flat ground Tuesday but hasn't had his bullpen scheduled.

"How far away, I don't know right now," Bosio said on the Mully and Hanley Show on 670 The Score on Wednesday morning. "Right now, it's really a day-to-day thing. We got good reports from the trainer yesterday, good reports from Jake, had a nice throwing session where he got it up to about 120 feet pretty effort-less. It's so important that there's obviously no setbacks. He's trying to do everything he can within reason. We got to be smart about this. We got to make sure he's healthy, because any tweak at all could cost him the rest of the regular season. Now, I don't know how many starts he's going to have. I don't have that crystal ball, but he is progressing. It is getting better. That's all I can say. It definitely could've been a lot worse."

Arrieta is 14-9 with a 3.48 ERA and 1.20 WHIP this season.