The strained left oblique will definitely keep Hiroki Kuroda out longer than his 15-day DL stint. After playing catch on Monday, he did not attempt to do so the next 2 days.
It's a blow for the Dodgers because he was their Opening Day starter, and they don't have a whole lot of depth for the rotation like they have had in years past. Well, I should say there's not as much reliable depth, because the jury is still out on guys like Eric Stults, James McDonald, and Jason Schmidt (remember him?).
If Stults is able to pitch well like he did last start and in spot starts last year, this should not be a big deal (he goes again tonight against the Giants). If he struggles, then it's a problem. McDonald got one start and was really all over the place, getting shelled against the Diamondbacks. He should get another start on Sunday against the Rockies, but who knows how long he'll last in that game.
As for Schmidt, he threw 73 pitches in 5 innings of an extended Spring Training game. Depending on how his body reacts that (and who knows how that'll be), he could be due for a Minor League rehab assignment soon. In other words, he won't provide any immediate help. Down the line is where they're aiming.
So really, a lot depends on if Stults can continue his solid starts. After watching how great Randy Wold, Chad Billingsley, and Clayton Kershaw were in their last starts, then Kuroda's loss isn't as glaring. If Stults can join that club, then Kuroda can take his time healing up.