A rough May has gotten even worse for the first-place Diamondbacks, as they have announced that center fielder A.J. Pollock has an avulsion fracture in his left thumb. The expectation is that Pollock will miss four to eight weeks. Pollock injured himself on a diving attempt in the outfield Monday night.

The timing couldn't be much worse. The Diamondbacks are on a six-game losing streak and have lost nine of their last 12 games. Pollock has been their best player to date, too. He's hitting .293/.349/.620 (150 OPS+) with 10 doubles, three triples, 11 homers, 33 RBI, 23 runs and nine steals. 

Pollock's breakout season was 2015, but he fractured his elbow late in spring training in 2016 and just finally had gotten himself back to an All-Star level. He entered Tuesday leading the NL in slugging percentage and ranking second in WAR to Nick Markakis

The Diamondbacks do have the depth to cover the outfield, as Jarrod Dyson can take over center until Pollock is able to come back. Of course, Dyson is only hitting .184/.245/.333 to this point. 

As a corresponding move to placing Pollock on the DL, the D-Backs have recalled power-hitting first baseman Christian Walker, and he's been getting some time in left field in the minors. David Peralta could slide over to center field if they wish to start Walker in left. 

Walker, 27, hit .309/.382/.597 with 32 homers and 114 RBI in 133 games for Triple-A Reno last season. He's a career .167/.297/.444 hitter in the majors, but it's only been 64 plate appearances over the course of four different seasons. 

Chris Owings could also see increased playing in the outfield, as he was filling in with Steven Souza hurt. 

All of these different options, of course, are much worse for the Diamondbacks than having Pollock in there. They'll have to make do for at least a month.