It was the fourth time in his last five starts that Santiago logged no more than four innings, with the long exception being a May 31 start against Detroit in which he gave up six runs.
"He's pitched some really good games this year for us, and it seems like it's been one extreme or the other," Scioscia said. "Too many times with Hector we're looking at the second inning and having to get somebody up."
After throwing eight shutout innings against Seattle on May 15, Santiago has yet to give up fewer than three runs in a start.
"It just seemed like everything was going the right way, but right now it looks like a slump," Santiago said. "I just have to keep going and see if I can get things going the right way."
On Friday, Santiago had allowed a single on a pitch that jammed Jason Kipnis and was working a 2-2 count with two outs to Indians first baseman Mike Napoli in the first. Napoli fouled off the next pitch, and as Santiago stepped off the mound he grabbed at his right hamstring.
He remained in the game after some warmup tosses, but subsequently gave up a Napoli RBI double to left. The next batter, Carlos Santana, did the same. Michael Martinez hit an RBI single to center, and another run came home on a throwing error from Yunel Escobar.
"It kind of carried over," Santiago said of the injury. "You're worried about [the hamstring] and just trying to adjust to that and make sure it doesn't fire up again."
Santiago recorded just one out in the second inning, on a sacrifice fly, allowing two more runs to score before exiting with two runners on and a 6-1 deficit.
While Santiago said the hamstring feels fine, his recent stretch has been alarming.
"I'm making the same pitches I did when I would throw eight scoreless or seven scoreless, but right now it just seems like it's snowballing and carrying over from each start," Santiago said. "The last five starts have been very frustrating."
With starters Garrett Richards, Andrew Heaney, C.J. Wilson, Tyler Skaggs and Nick Tropeano down with injuries, Santiago's struggles have been even more impactful. The bullpen, taxed over a four-game sweep at the hands of the Yankees, was called on yet again for heavy duty.
They delivered, tossing 7 2/3 scoreless innings, but Scioscia wasn't in the mood for any kind of silver lining.
"I don't know if you can take too many positives away when you're looking up at a [6-1] score in the second inning," he said.