Tossing 104 pitches in just five innings against the Rangers, the Angels right-hander gave up two runs on seven hits and walked two for his sixth loss of the season.
Haren came into game having given up just one run and no walks over a 16-inning stretch during his past two starts.
"Any time you're throwing 100 pitches in five innings, it's going to wear you down," Haren said after the game. "You're not going to be at your best if you're throwing 25, 30 pitches an inning. You have to tip your cap to them."
He'll try and correct that against the Rockies on Saturday at Coors Field.
Haren will be up against Jeff Francis, who will take the hill for Colorado after the team reached an agreement with the left-hander on Thursday.
Francis, the team's ace during the 2007 World Series, signed a Minor League contract this offseason with the Reds and went 3-6 with a 3.72 ERA for Triple-A Louisville.
After pitching a shutout Sunday, he exercised an option in his contract by asking for his release.
His signing is perfect timing for a Rockies rotation that is not only inexperienced but dealing with its fair share of injuries.
Francis went 55-50 for the Rockies in six seasons, including 17-9 in 2007.
Angels: Hunter's hot-hitting during Interleague
Something about Interleague Play seems to bring out the best in Torii Hunter. The Angels outfielder, who came into Friday's game against the Rockies batting .322 in Interleague Play since 2007, tallied two home runs and six RBIs in Friday's game.
His .370 clip during Interleague Play last season was the seventh-best in the American League.
Kendrys Morales is batting .321 (18-for-56) with two doubles, four home runs and 12 RBIs in his past 15 games.
Rockies: Tulowitzki progressing
Rockies shortstop Troy Tulowitzki, eligible to return from a left groin strain on June 15, did light running at Coors Field on Friday.
"I saw him in the office and he's beginning to feel good," Rockies manager Jim Tracy said, adding that Tulowitzki is "progressing very nicely."
Left-hander Jorge De La Rosa, who is coming off Tommy John surgery and has had his rehab assignments halted twice, is pain-free but the Rockies will wait another day or so before he plays catch.
Although the Rockies are 0-4 to begin Interleague Play this season, Colorado still remains the National League's best team in Interleague Play since the 2006 season at 56-41.
The Angels have won all six series against the NL and have won nine of their past 10 series in Interleague Play spanning back to 2010.