PHOENIX -- The D-backs learned the magnitude of their latest loss Tuesday when center fielder A.J. Pollock was placed on the 10-day disabled list with an avulsion fracture of his left thumb.
Pollock could be out from four to eight weeks. Christian Walker was called up from Triple-A Reno.
"Losing A.J., the way he was playing, is a pretty big blow, but no one is going to feel sorry for us," D-backs general manager Mike Hazen said. "We've got to pick up and move on. We feel bad for A.J. He was in the midst of having a great season and he'll be back to continue that season at some point. But in the interim, we're going to have to figure out how to put the pieces together to cover for him, that spot, and win games."
Pollock was hitting .293/.349/.620 and he led the team in doubles (10), homers (11) and RBIs (33), while topping the National League in slugging percentage (.620).
Pollock injured the thumb with two outs in the ninth inning on Monday night, when he made a diving attempt on Tyler Saladino's fly ball.
Pollock came up short in the dive and then rolled over his left hand. Meanwhile, Saladino circled the bases for an inside-the-park homer.

"It's just a very, very unfortunate situation," D-backs manager Torey Lovullo said. "But once again, it's that next-man-up mentality. We feel that we've created depth here for these situations and it's time for guys to step up and take advantage of some opportunities until A.J. rejoins us."
At least initially, the team plans on platooning the left-handed-hitting Jarrod Dyson and righty Chris Owings in center field.
Dyson has extensive experience in center, while Owings played 49 games there in 2016 after Pollock fractured his elbow just prior to Opening Day.
"It was strongly recommended to me that he would be able to [play center] by several people who have seen him," Lovullo said. "I have never seen him as a center fielder. There's some general familiarity from what he did there in '16, and I signed off on it because I believe in the coaches that were expressing the fact that he could do it. The two of those guys will split time and I know they're more than capable of doing a great job." 

Walker's best position is first base, but after spending a few weeks in the big leagues earlier this year, he has been playing some left field for Reno.
Lovullo said that while Walker is not a candidate to start in left now, he could see some time there if needed.
As for going outside the organization, Hazen said it is still too early to be discussing trades. That could always change following next month's Draft.
"I think we have enough versatility," Hazen said. "I think we have enough players on our bench that can fill in in more full-time capacities. We'll play matchups how we need to and we'll be OK."