Mark Trumbo’s walk-off homer delivers Angels’ seventh win in a row

On the night the Angels got their heart and soul back, they may have wound up losing their best arm.

What they didn’t lose was the game, rallying for a 9-8 victory over the New York Yankees on Mark Trumbo’s walk-off home run leading off the ninth inning Monday. That ran the team’s winning streak to seven games in a row, its longest since July 2009, and lifted it to .500 for the first time since the season’s opening week.

But it may prove to be a costly loss because, with Torii Hunter watching from the dugout for the first time in two weeks, ace Jered Weaver hobbled off the mound after 12 pitches because of a lower-back injury.

“I never felt anything like that before. It felt like somebody stabbed me in the back,” Weaver said. “You can’t really do much about it. It’s very disappointing.”

Weaver, who was still in pain after the game despite taking muscle relaxants, said he will have an MRI exam Tuesday.

“I guess I don’t really have any answers right now,” he said. “I just have to wait for the MRI and X-rays to come back. So we’ll keep our fingers crossed.”

Even if Weaver avoids the disabled list, the team is almost certain to make a move Tuesday after watching its bullpen throw 23 innings in the last week.

“We’re going to look at a couple of things now and tonight and tomorrow and see what we need to do,” Manager Mike Scioscia said.

Weaver has been on the DL once in his six-year career, missing two starts in 2007 because of biceps tendinitis. He began Monday tied for second in the American League in wins (six) and third in earned-run average (2.61).

And in his last home start he pitched a no-hitter.

This time he didn’t retire a batter, giving up two singles before Alex Rodriguez knocked in the Yankees’ first run with a sharply hit grounder that shortstop Erick Aybar misplayed. Then, after throwing a 1-and-0 fastball for a strike to Robinson Cano, Weaver bounced off the mound in pain.

After taking a few moments to gather himself, Weaver tried to throw a warm-up pitch. But as the ball floated to the plate Weaver again felt pain before storming toward the dugout.

Too bad Weaver couldn’t stick around for the rest of the 3-hour 38-minute game because it was a doozy, featuring 25 hits, four errors, four home runs and nine pitching changes. And the crowd of 44,016 that saw it marked only the second sellout of the season for the Angels.

Neither side went down in order until the eighth, when Jordan Walden got the Yankees on 10 pitches, striking out two. He escaped a bases-loaded jam in the ninth, getting six outs for the first time in his career, and then was rewarded with the win when Trumbo ended it in the bottom of the inning with a home run inside the foul pole in left field for his team-leading eighth home run.

The Yankees took a 3-0 lead in the first, batted around against Weaver and reliever Bobby Cassevah, but the Angels came right back in the bottom of the first, scoring four times, including a two-run single to center field by Howie Kendrick.

After Curtis Granderson tied the score in the second with a home run, Kendrick put the Angels in front with a third-inning sacrifice fly.

The teams traded runs again in the middle innings on homers by Mike Trout and Mark Teixeira. Then after Kendrys Morales’ two-run double in the sixth appeared to give the Angels some breathing room, the Yankees came back to tie it again in the seventh on a two-out, two-strike, two-run double by Russell Martin.

kevin.baxter@latimes.com