CHICAGO -- With 10 days to go until the Trade Deadline, D-backs GM Mike Hazen has a tough decision to make, and it’s not about whether his team will be a buyer or seller.

Following a stretch of good play by the D-backs, including Friday afternoon’s 5-2 win over the Cubs at Wrigley Field, Hazen is looking to buy at the Deadline, but the question he faces is whether he needs to add a starting pitcher or not.

The D-backs' rotation has been decimated with injuries this year. Zac Gallen is back, but he missed a month at one point with a strained right hamstring. Currently, three-fifths of the team’s projected Opening Day rotation is on the IL -- Merrill Kelly (right shoulder strain), Eduardo Rodriguez (left lat strain) and Jordan Montgomery (right knee inflammation).

Depth starting pitching options have had issues, too. Blake Walston is on the IL, Tommy Henry is in Triple-A Reno, as is Slade Cecconi, who might fit better as a reliever for the D-backs if/when he gets called back up.

The recent reports have been encouraging on all three of the pitchers on the IL.

Montgomery threw a simulated game Thursday, and if he continues to report no issues with his right knee, he will likely rejoin the team after this series with the Cubs.

Kelly and Rodriguez are further behind Montgomery, but both could return in August.

“Everything has been great from what I’ve heard,” Hazen said of Kelly and Rodriguez. “All the markers. No issues. No residual soreness. No extra days in between. It’s been, coming off the mound, ‘Feel great,’ next day, ‘Feel great.’ I think we’re steaming towards wherever the progression is going to take them. I don’t really know exactly what that day looks like. But everything has been good.”

If those two come back healthy to team with Gallen, Montgomery and Brandon Pfaadt, the D-backs will have a strong rotation. Even if not all of them are able to come back, Arizona could still be in good shape given the way Ryne Nelson has thrown lately.

The right-hander held the Cubs to one run over 5 2/3 innings while striking out a career-best nine on Friday. Nelson has allowed just six earned runs over his past four starts as he’s helped stabilize the rotation.

Another option is rookie Yilber Diaz, who has been outstanding in his first two big league starts.

All of which begs the question: Should Hazen be looking to add another starter at the Deadline?

“It’s a very interesting question,” Hazen said. “Long-term starting pitching is still going to be something I’m going to explore no matter what if it’s multiple years of control because I feel like we have to. We always have to look out for our rotation a couple of years down the line. I think if I feel very confident when Monty comes back and then [Kelly and Rodriguez] are right around the corner, I probably would not place as much emphasis on it. But I don’t know. It obviously depends on if Nelly and Yilber keep throwing the ball really well, that’s going to impact how this goes.”

While Hazen will try to buy, it won’t be a situation where he empties the farm system, so there are only so many pieces he can acquire.

So if he feels good about the rotation over the next 10 days, that would allow him to use his trade chips to bolster other areas of the team.

“I’d love to be able to target down the needs to bullpen, position-player fit somewhere, and just go with that,” Hazen said. “That would be great. I don’t know if we’re going to just be afforded that opportunity.”

The next 10 days will help answer that question both on the field and in the trainer’s room.