ANAHEIM  (AP) — Los Angeles Angels ace Jered Weaver left his start against the Yankees in the first inning Monday night after apparently injuring his back while pitching.

Weaver gave up two hits and a run in his first three batters before pulling up awkwardly after pitching to cleanup hitter Robinson Cano.

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Weaver walked around the mound and eventually attempted to throw a warmup pitch that didn’t have much zip, and he went to the Angels’ clubhouse with their training staff. The Angels eventually announced Weaver apparently has a lower-back injury.

Weaver began the night 6-1 with a 2.61 ERA, second in the AL in victories. Any extended absence could be disastrous for the Angels, whose touted starting rotation hasn’t been impressive beyond Weaver’s steady play.

The right-hander was making his first start at Angel Stadium since throwing a no-hitter May 2 in Anaheim against Minnesota. Weaver was 4-0 with an 0.83 ERA at home this season.

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Weaver went 18-8 with a 2.41 ERA last season, making his second All-Star team and finishing second in the AL Cy Young voting.

Derek Jeter led off with a single against Weaver. He advanced to second on Curtis Granderson’s single and then scored when Erick Aybar booted Alex Rodriguez’s grounder.

After Weaver left, reliever Bobby Cassevah struck out Cano, but walked Mark Teixeira and allowed Raul Ibanez’s sacrifice fly. Rodriguez scored another Yankees run when Cassevah made a poor throw to first base, allowing Nick Swisher to reach.

Cassevah retired Russell Martin on a bases-loaded flyout to end the inning with the Angels down 3-0.

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Los Angeles returned from a 10-game road trip on a six-game winning streak, while the Yankees had won five in a row.