"He wasn't extending the way he needs to," Scioscia said. "He needs extension to get the fastball down on both sides of the plate. His last start wasn't what he wanted it to be."
Haren was charged with seven earned runs on nine hits in 4 1/3 innings in the Angels' dramatic come-from-behind victory against the Rangers. He had yielded four earned runs on 10 hits against the A's in his previous outing, ending a run of four consecutive wins and six in eight starts.
Scioscia said that the back issue flared up after the All-Star break, Haren having won the game before the intermission against Seattle at Angel Stadium with 8 2/3 innings of labor.
"He was battling it a little in Oakland," Scioscia said. "He felt much better in the last start. It isn't bothering him now. It's nothing he hasn't pitched with before."
After giving up more than one earned run just once in his first 11 starts, Haren has yielded four or more earned runs in four of his past 11 outings.