Martin Prado, one of the Yankees' hottest hitters, injured his left hamstring and was replaced by pinch hitter Chris Young in the ninth inning of the Yankees' 9-4 loss to the Red Sox Tuesday night.
Prado went 2-for-3 with a home run, his fifth as a Yankee. He is batting .381 with four home runs and 11 RBIs over his last 16 games.
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Prado was scheduled to get an MRI late Tuesday night and could be lost to the Yankees beginning Wednesday night. It was unclear when he was injured.
"That's not someone that we want to lose," manager Joe Girardi said. "He's played extremely well."
Young, who was released by the Mets last month, struck out on three pitches against Koji Uehara in his Yankees debut.
Young, who was given Alex Rodriguez's locker in the Yankees' cramped clubhouse, signed with the Yankees' Triple-A team last week.
In four games for Scranton/Wilkes-Barre, Young went 3-for-15 with one home runs and two RBIs. In 88 games with the Mets, he hit .205 with eight home runs and 28 RBIs after signing a one-year, $7.25-million free-agent contract.
"It worked out great for me," Young said of ending up on the Yankees.
The Yankees also called up catcher John Ryan Murphy, pitchers Preston Claiborne, Bryan Mitchell, Chase Whitley, Chaz Roe and Rich Hill, and outfielder Antoan Richardson.
The Yankees released pitcher Matt Daley, the Garden City product who had appeared in 20 games over the last two seasons, and designated outfielder Zoilo Almonte for assignment.
Masahiro Tanaka, who was shut down with "general arm soreness" last week, will throw a bullpen session later this week after playing catch Tuesday. Tanaka is still hoping to avoid Tommy John surgery.