Red Sox staff assistant Rob Leary was the one hitting the fungoes, and he was absolutely rifling them at Beltre.
"That's how I like it," Beltre said.
How many do you take?
"I don't count," he said.
For the record, it was close to 200 grounders, according to one Red Sox staff member.
The Sox already had conducted Thursday's daily infield drills, which usually last about 20 minutes, when Beltre asked for the extra work. He does it every day during spring training, but once the season starts, Beltre eases off a bit.
The best part about Beltre's extra work is that it's during batting practice. Yes, during batting practice. Right-handed hitters are drilling balls right at Beltre in between fungoes without the veteran third baseman even flinching.
(And remember, Beltre was the guy who sustained an injury last season after getting hit in the groin without wearing a cup.)
The Red Sox signed Beltre to a one-year contract worth $9 million this offseason, and his .957 career fielding percentage in 12 seasons is a major reason. (His career .270 batting average helped, too.) Beltre won Gold Gloves for the Seattle Mariners in 2007 and 2008, and the Sox are hoping for a repeat performance this season.
Beltre's defensive prowess is legendary. Even though he's a newcomer to Boston, a couple of former Red Sox players who have been his teammates know what he'll bring to the team.
Former Red Sox infielder and current Dodger Nick Green played with Beltre during the 2007 season in Seattle.
"I think he's the best defensive third baseman in the game," Green said. "I like the way he plays over there. He's one of the best."
Green played only six games for the Mariners that season and never saw one of Beltre's marathon fungo sessions.
"I didn't see any extra madness like that, but it was late in the season," Green said. "I'm sure he's just getting ready for the season. That just shows you the hands he has and how good he is over there. I don't think I would do that during BP."
Beltre was starting for the Los Angeles Dodgers in 2002 when he was 23 and already had five years of big league experience when another young infielder, Joe Thurston, was just getting his start with Los Angeles.
"When I first saw him, I couldn't believe he was as young as he was and talented as he was," said Thurston, who now plays for the St. Louis Cardinals. "He was only a year older than me, but he already looked like a man out there. He's always a positive player, a guy who wanted to be the best he could be. He wanted the best out of his teammates, too. I really enjoyed playing with him and being around him."
Thurston, who was in the Red Sox organization in 2008 and played four games for Boston, knows Beltre will be a huge asset.
"There aren't too many guys as good as Adrian," Thurston said. "He can help any club with that defense he has. He can help with his offense as well. I've seen him do amazing things at the plate. Defensively, he's a very good player at third base. Any time I'm playing third, I think about that guy."
The Red Sox's starting lineup against the Twins Thursday night was an impressive one from a defensive standpoint, especially the infielders. As Josh Beckett made the start on the mound, he had Beltre, Marco Scutaro, Dustin Pedroia and Kevin Youkilis behind him. No doubt it's an upgrade from a year ago, and the entire pitching staff knows it.
"You don't have to make the perfect pitch," Beckett said. "You make a decent pitch, and the guys behind you are going to pick you up. [Pitchers] haven't talked about it, but it's just known. The defense is really going to help us. Not making the perfect pitch in a bad situation, if we're behind in the count, or we've got guys on base, you feel like you can make a good pitch and if the ball is put in play, you've got a good chance of getting some outs."
Beltre is going to be a key component of getting outs.
"He just makes it look too easy," Green said. "It's not fair, especially for a guy like myself who has to grind every day to try to make it look easy."
When Beltre completed his extra work Thursday afternoon, he stood in a sea of baseballs near the third-base coach's box. Leary walked over, and the two collected the pearly whites and placed them back in the bucket.
"That's why he's so talented," Leary said. "Because he works."
Joe McDonald covers the Red Sox and Bruins for ESPNBoston.com.