"He was doing his agility drill and stuck a spike; [the] spike caught," manager Joe Torre said. "They don't think it's anything, just rolled it a little bit. It may set him back a couple of days."
The 20-year-old right-hander is widely regarded as the Yankees' top pitching prospect. He has been on the disabled list since straining his left hamstring in a May 1 start against the Texas Rangers, in which he was working on a no-hitter.
General manager Brian Cashman said that Hughes will be sent for an MRI on either Friday or Saturday. Torre said that the injury is not expected to significantly alter Hughes' projected return date.
Hughes threw 35 pitches off a full mound on Wednesday in Tampa, Fla., his first bullpen session since straining the left hamstring, and reported no problems.
At the time of the hamstring injury, it was estimated that Hughes could miss as much as six to eight weeks of action. Torre said that projecting Hughes' return to rotation in mid-June is "certainly possible."
He's The Boss: Jason Giambi acknowledged that he'd heard what owner George Steinbrenner had to say about him in an interview with The Associated Press on Friday, but beyond that, Giambi wasn't saying much.
"He has that right," Giambi said. "He's my boss."
Steinbrenner, 76, did not respond positively to the comments Giambi made last week to a USA Today reporter during the club's series in Chicago, when Giambi said he was wrong for having done "that stuff" -- alluding to his past use of performance-enhancing drugs -- and suggested that Major League Baseball owed its fans an apology for allowing the substances to infiltrate the sport.
Commissioner Bud Selig is likely to decide in the next week or two if Giambi will be disciplined for his comments.
"He should have kept his mouth shut," Steinbrenner said. "The matter is in the hands of the baseball Commissioner."
Though Giambi declined to discuss Steinbrenner's comments further, Torre said that he believes Giambi is sensitive to the statements being made concerning him.
"Jason cares," Torre said. "He cares a great deal about his teammates, about the uniform he wears, and I don't think it's going to affect what happens on the field.
"Now, saying that, I don't want you think he doesn't care what's said, but he seems to be able to block it out at the right time. I'm sure he listened, or took in the remarks, and [they] meant something to him."
Giambi moved up to sixth in the Yankees' lineup on Friday, as he entered play against the Angels batting .260 with six home runs and 19 RBIs. Slowed by a bone spur and plantar fasciitis in his left heel -- which were treated by orthotic inserts that arrived before last weekend's series against the Mets -- Giambi had just two hits in his previous 34 at-bats.
"I'm just trying to get my swing back," Giambi said. "I'm just trying to get it all together. The orthotics definitely helped, but it's going to be a gradual process."
Mr. May: Good defense at first base and a solid line at the plate -- a .308 average, six doubles, two home runs, 12 runs scored and eight RBIs in 20 games.
Don't look now, but these were Doug Mientkiewicz's numbers for the month entering Friday's game. The stats may seem difficult to believe after Mientkiewicz posted a .154 average in 52 April at-bats.
But Mientkiewicz -- even though he insists he's still not in a groove at the plate -- is finally producing the way the Yankees had hoped he could.
"You have a good month, and your average can jump 50 to 60 points," Mientkiewicz said. "You don't want to get too wrapped up or giddy about it."
Torre kept faith in Mientkiewicz's hitting even during his April slump. Of course, the reason he played regularly was because of his strong defense, but the upper-deck home run he hit off Boston's Curt Schilling on Wednesday night couldn't hurt.
"Dougie is working at it. He worked at it all spring," Torre said. "It was a nice game the other day against the not-so-easy pitcher to handle. He's a hard-nosed kid. He's going to stick his face in it and try every which way to help this ballclub win ballgames.
"Obviously, he can't do it with his legs, but the defense part of it and, of course, the three-hit game the other day had to make him feel good. We trust him over there at first base, and so far the hitting -- every once in a while he surprises us with a home run."
Come on up: Kei Igawa showed enough signs of improvement in his start on Thursday for Class A Tampa that he will enjoy a change of venue for his next time on a mound. Igawa will be summoned to join the Triple-A Scranton/Wilkes-Barre rotation for his next start, pitching on Tuesday -- one day after Roger Clemens.
Igawa, 27, was Tampa's winning pitcher in a 9-8 victory over the Vero Beach Dodgers at Dodgertown on Thursday, throwing five innings and allowing two runs on four hits.
He walked one and struck out four in his second appearance for Tampa, and though Torre said reports indicated that Igawa didn't show much velocity, his delivery was more mechanically sound.
"I know they were just trying to keep him over the rubber, where he wasn't tipping and dragging his arm," Torre said.
Igawa appeared in six games (five starts) for the Yankees this season, going 2-1 with a 7.63 ERA. He signed a five-year, $20 million contract in January after the Yankees offered a $26 million posting bid to acquire his rights from the Hanshin Tigers of the Japanese Central League.
That's a wrap: Right-hander Darrell Rasner, on the shelf for up to three months with a broken right index finger, had the heavy bandage removed from his surgically repaired digit. Rasner said he'd been forced to protect the wrap by showering with a plastic bag.
"At least now I can brush my teeth," Rasner said.
Coming up: The Yankees and Angels meet for the second game of their three-game series on Saturday afternoon, as right-hander Chien-Ming Wang (3-3, 4.28 ERA) gets the call for New York. Right-hander Kelvim Escobar (5-2, 2.82 ERA) makes the start for the Angels, with first pitch scheduled for 1:05 ET.
Bryan Hoch is a reporter for MLB.com. Caleb Breakey, an associate reporter for MLB.com, contributed to this report. This story was not subject to the approval of Major League Baseball or its clubs.