ANAHEIM -- Highly regarded Mariners outfield prospect Julio Rodriguez has a hairline fracture in his left hand and is expected to miss four to six weeks, Mariners director of player development Andy McKay said Friday.

First baseman Evan White, another of Seattle’s top prospects, is also on the injured list with a mild hip flexor strain at Double-A Arkansas, but is progressing well and is expected to be activated early next week, McKay said.

The 18-year-old Rodriguez was off to a hot start for Class A West Virginia and is the Mariners’ No. 5 prospect, per MLB Pipeline. He was hit in the hand by Augusta starter Jake Wong last Friday, though initial X-rays didn’t reveal a fracture and he was only expected to miss a few days. Subsequent tests showed a fracture in the third metacarpal on his left hand.

Rodriguez was batting .355/.444/.452 with three doubles and three RBIs in 31 at-bats in his first nine games in the South Atlantic League.

White, the Mariners’ first-round Draft pick in 2017 out of Kentucky and No. 4 prospect, hit .308/.367/.385 with two doubles and three RBIs in 26 at-bats over his first seven games before injuring his hip on a checked swing last Thursday and he has sat out the past week.

In other Mariners’ Minor League news:

• Reliever Dan Altavilla and Nabil Crismatt were reassigned from Triple-A Tacoma to Arkansas as the club swapped right-handed pitchers, bringing up Parker Markel and Aaron Northcraft. Altavilla opened the season with the Mariners, but has struggled at Tacoma with an 11.57 ERA with six earned runs on three hits and five walks in 4 2/3 innings over five appearances. He’ll be given a chance to get things squared away at Arkansas. Markel will be given a shot at Tacoma after striking out 18 batters in 7 2/3 scoreless innings at Arkansas, allowing just two hits and two walks. The 28-year-old right-hander signed as a Minor League free agent in September after pitching independent ball last season. Northcraft, 28, posted a 1.69 ERA over 5 1/3 innings in Double-A in his first action in pro ball since 2016.

• Outfielder Tito Polo was released from his contract at Triple-A Tacoma after being suspended by the Pacific Coast League for an on-field incident. Polo was in the Mariners’ Major League camp this spring and hit .263 with four doubles in 10 games for the Rainiers.

• After a slow start at Class A West Virginia, the Mariners' No. 2 prospect Jarred Kelenic has heated up in a hurry. Kelenic, acquired from the Mets in the Robinson Cano/Edwin Diaz deal, went 2-for-25 in his first seven games, but has hit .484 (15-for-31) with a home run and seven RBIs over his past seven.