SAN FRANCISCO — It could have been much worse.

That was the common consensus inside the visitors’ clubhouse at AT&T Park Thursday afternoon when word came down about the diagnosis of D.J. LeMahieu’s left thumb injury.

Yes, the Rockies’ all-star second baseman has a small fracture to a bone in his thumb. Yes, LeMahieu could be out of action for up to three weeks, depending on the level of pain. And yes, Colorado’s sputtering offense will miss LeMahieu’s steady bat through a stretch off key games against National League West foes.

But LeMahieu suffered no ligament damage, no surgery will be required, and once the pain and swelling subside, LeMahieu can begin gripping a bat again. He hoped to be playing catch and swinging a bat in a week to 10 days.

“Overall, I think it’s really good news,” said LeMahieu, whose left hand was tightly wrapped Thursday afternoon. “It’s still pretty sore, so I didn’t really know what was going on. I had never really had that type of pain before. But overall, the news was good. It was not great news, but it certainly could have been worse.”

LeMahieu was hitting .279 with five home runs and 13 RBIs and had become Colorado’s leadoff hitter.

For now, Daniel Castro and Pat Valaika will fill in for LeMahieu. Manager Bud Black said he will make the decision on whom to start on a “day-to-day basis.”

However, another possibility could be the promotion of infield prospect Garrett Hampson, who was moved from Double-A Hartford to Triple-A Albuquerque on Thursday. The athletic Hampson, 23, hit .304 with four home runs, 15 RBIs and 19 stolen bases in 20 attempts for Hartford. He is a leadoff hitter.

According to the Rockies, LeMahieu suffered a “very small” fracture to the volar radial bone on the outside of his left thumb while taking an awkward swing in Sunday’s game against Milwaukee. Most thumb injuries in baseball happen to the inside of the thumb and are usually more serious. For example, Arizona lost center fielder A.J. Pollock on Monday with an avulsion fracture in his left thumb and he could be out as long as eight weeks. Pollock injured his thumb diving for fly ball during a loss to the Brewers. Pollock rolled his glove hand awkwardly trying to snare the ball.

“You hope for the best and you fear for the worst,” Black said of LeMahieu’s injury. “But the consensus from the doctors was, overall, optimistic. At this point, we won’t know until he starts doing some activity if there is going to be pain and discomfort. It looked to the specialists that DJ’s thumb is going to be OK — in time. We don’t know how long.”

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The problem is, the Rockies can ill afford missing a major part of their offense. Valaika was hitting .115 heading into Thursday’s game, and Castro was batting just .148.

“It’s tough news about DJ,” Valaika said. “He’s one of the best, if not the best. But this is part of the game and I have to be ready whenever my name is called. I’m very comfortable at second. The majority of my time in baseball has been at second and short, so I feel good at either place.”