The Chicago Cubs know as well as the rest of the league they’ll be pursuing starting pitching at the trade deadline.

At this point, the only uncertainty is how many starters Jed Hoyer will push for at the end of next month. Former general manager Jim Bowden believes Zac Gallen of the Arizona Diamondbacks is the best choice for the Cubs.

“The Cubs could use one more starting pitcher and Gallen would be the perfect target even though he’s having a down year (4-8 with a 5.15 ERA),” wrote Bowden. “Two years ago, he was the starting pitcher for the NL All-Star team and finished third in the Cy Young Award voting. Last year, he went 14-6 with a 3.65 ERA.”

This season has been far from kind for Gallen, but there is still some optimism he can turn things around. His WHIP is right around where it has sat for most of his career, falling in the 1.1-1.3 range. However, he’s giving up a lot of hard hits, and his strikeout rate is only in the 47th percentile, according to Baseball Savant.

“Gallen would need to have three to four strong starts before the deadline for the Diamondbacks to get the strong prospect package they’d want, but if they fall further out of contention, they might have to trade the impending free agent,” wrote Bowden. “He needs to improve the command and late finish on his fastball to get back to where he needs to be.”

If Chicago was to pursue Gallen, it would be paying rental price for him. The 29-year-old pitcher is set for free agency at the end of the season, so the Cubs would simply be on the hook for the remainder of his $13.5 million salary this season plus the package going back to Arizona.