OAKLAND, Calif. >> Mike Scioscia’s rotation is struggling with consistency, and it is costing the Los Angeles Angels key games.

Jerome Williams (5-7) dropped his second straight start to Oakland and failed to go more than five innings for the fifth straight start, taking a 6-4 loss Friday night to the AL West-leading Athletics.

“You need five guys,” Scioscia said. “It’s tough to build momentum without the starting five doing what they can do. We need these guys to come out and give us a chance to win when they take the ball. At times it’s been a little spotty.”

Williams yielded four runs and six hits in five innings. The A’s pushed his pitch count up in a hurry, and he threw 103 in all over five innings — his fifth straight outing of five or fewer innings.

The Angels also ran into one of baseball’s hottest pitchers, a familiar one at that.

Bartolo Colon took over a share of the major league lead for wins two months past his 40th birthday and going on a year since he received a 50-game suspension for a positive testosterone test.

Colon won his 14th game, backed by Jed Lowrie’s homer and two-run single and a two-run drive by Stephen Vogt.

“I wouldn’t have thought this,” Colon said. “I have surprised myself right now because I didn’t know I was going to share the lead with the other pitchers. I am proud.”

The All-Star right-hander won his third straight decision while facing his former club. He won the 2005 AL Cy Young Award with a 21-8 year for the Angels.

Mike Trout hit a two-run homer in the first on a ball he crushed into the elevated seats in left-center, then Colon settled in nicely against Los Angeles’ loaded lineup.

Colon (14-3) allowed two runs and seven hits in six innings, struck out two and walked two. He has won 11 of 12 decisions since losing May 9 at Cleveland and has lost just once since turning 40 on May 24.

“I’d be lying if I said I thought he’d be 14-3 right now,” manager Bob Melvin said.

Jerry Blevins walked the first two Angels of the ninth. Grant Balfour relieved and allowed Albert Pujols’ two-run single. Balfour then struck out Josh Hamilton to end it for his 27th save after blowing his first opportunity since April 29, 2012, Tuesday night at Houston — snapping his franchise-best streak of 44 saves in a row.

Williams lost his fifth straight decision and has a seven-start winless stretch since beating the Orioles in Baltimore on June 12. Williams, who pitched for Oakland’s Triple-A Sacramento club in 2009, received a mound visit after Coco Crisp followed Eric Sogard’s tying single in the second with a base hit.

“I feel like I’m going in the right direction. I just didn’t execute a couple pitches and I got hurt on them,” Williams said. “Just got to minimize the mistakes and look at the positives and go out there and try to get positives.”

Crisp started a nice double play in the third when he caught Pujols’ fly and threw to second baseman Sogard to get Trout after he reached on an infield single.

Crisp was “shocked” he made the play.

“Just like any other fly ball, guys are going to try to tag on me because I don’t have the strongest arm. Today, my arm actually felt pretty good,” he said. “That’s not my forte.”

Said Colon with a grin: “He surprised the whole world with that throw, and the fans.”

After his Aug. 22 suspension last year carried into this season, Colon now is among more than a dozen players being investigated by Major League Baseball for ties to a Florida clinic accused of distributing performance-enhancing drugs. He is concentrating only on his pitching.

On Friday, he helped the AL West-leading A’s bounce back from an 8-3 defeat in Thursday night’s series opener.

Lowrie homered in the bottom of the first to get the A’s to 2-1, then singled home two runs to put his team ahead in the second two batters after Sogard’s tying single. Vogt connected in the sixth, and he thoroughly enjoyed catching Colon. The pitcher shook him off 10-12 times.

“It’s fun to watch him just move the ball around the zone, move the ball in and out,” Vogt said. “He really is special.”

Angels second baseman Tommy Field singled in the second for his first major league hit since Sept. 28, 2011, while with Colorado.

NOTES: Crisp passed Jose Canseco for sixth place on Oakland’s career stolen base list with 136. Reggie Jackson is fifth (144). … Angels 2B Howie Kendrick was out of the lineup because he needed a day off, Scioscia said, adding that Kendrick will return Saturday. … LHP Vargas, sidelined by a blood clot in his left armpit area, continues to throw off the mound every three days and should be able to rejoin the Los Angeles rotation soon. … The teams will wear throwback uniforms from 1969 for Saturday afternoon’s game as Oakland hosts a 60s theme day.