Diamondbacks Place Zac Gallen, Christian Walker On 10-Day IL

5:46pm: Early test results on Gallen’s elbow have been “encouraging,” Bob Nightengale of USA Today tweets.

5:02pm: The Diamondbacks have placed right-hander Zac Gallen (elbow sprain) and first baseman Christian Walker (right oblique soreness) on the 10-day injured list, Nick Piecoro of the Arizona Republic reports. The team also selected righty Seth Frankoff, recalled infielder Andrew Young and designated infielder/outfielder Wyatt Mathisen for assignment.

Gallen was supposed to start Wednesday against his former team, the Marlins, but he’ll instead be out for a while longer. He’s dealing with a “minor sprain of one section of his UCL in his right elbow,” according to manager Torey Lovullo, who added that the team will “reassess in a couple weeks” (via Piecoro). If the issue is anything but “minor,” it would be a terrible development for Gallen and the D-backs, as the 25-year-old has thrived since they acquired him from Miami for second baseman Jazz Chisholm in 2019.

Chisholm has turned into a valuable player in his own right since the deal went down, but Arizona’s surely pleased with Gallen’s output in its uniform. Gallen owns a 2.85 ERA in 142 1/3 innings as a Diamondback, including a 3.04 mark over 26 2/3 frames this year, and has posted a 28.4 percent strikeout rate against a 9.7 percent walk rate.

This is the second IL placement of the year for Walker, who has landed on the shelf both times because of his oblique. Even when healthy enough to play this season, Walker has fallen well short of the above-average numbers he registered from 2019-20, having hit a disappointing .203/.268/.313 through 71 plate appearances.

Mathisen has joined Walker in seeing time at first base for the Diamondbacks, who will have a week to trade the 27-year-old or get him through waivers. Mathisen has been tremendous at the Triple-A level, where he has slashed .267/.370/.514 with 32 home runs in 627 trips to the plate. However, that success hasn’t translated to the majors, as Mathisen has batted .159/.298/.290 over a much smaller sample size of 84 plate appearances. Mathisen has two minor league options left, so perhaps a team seeking offensive depth will take a chance on him.

Frankoff, 32, signed a minor league deal with the Diamondbacks last winter after the Mariners outrighted him. He had a productive run with the Korea Baseball Organization’s Doosan Bears from 2018-19, during which he combined for a 3.68 ERA in 266 2/3 frames. Prior to that, almost all of his career was spent in the minors with the Athletics, Dodgers and Cubs. Frankoff only has 4 2/3 big league innings under his belt.