SEATTLE -- Mariners center fielder Julio Rodríguez has started running in his recovery from a high ankle sprain, but the team is still uncertain about the timeline for when its young star could return to the lineup.

General manager Justin Hollander said Friday that Rodríguez had started "linear running" and that he was recovering at "a high rate of speed." Hollander said the nature of the injury makes it difficult to know when Rodríguez will be ready to start doing the cutting and lateral movements that he'll ultimately need to return to Seattle's lineup.

"Julio is generally a fast healer and is younger, faster and stronger than almost anyone in the world so he is pushing it as much as he can. I know he wants to get back here," Hollander said.

Rodríguez suffered the ankle injury July 21 when he crashed into the center-field wall attempting to make a catch.

The update on Rodríguez came the same day Seattle placed reliever Gregory Santos on the 15-day injured list due to biceps inflammation, but with the hope it will be a brief absence. Santos left the mound in the middle of the eighth inning Wednesday after feeling discomfort in the arm.

Seattle also claimed right-hander Jonathan Hernández off waivers from Texas and designated for assignment right-hander Brett de Geus. Hernández was 3-1 with a 5.05 ERA in 26 games this season for the Rangers. He was designated for assignment by Texas on Tuesday.

Another uncertain timeline for Seattle concerns shortstop J.P. Crawford, who was out taking ground balls before Friday's game as he continues to recover from a broken pinky on his right hand. Hollander said Crawford would have another set of X-rays taken Monday, but he won't begin any progression in his baseball activities until Aug. 19, at the earliest.

"That will be four weeks. That's pretty aggressive, but that would be the absolute soonest. It just depends on what kind of healing we see," Hollander said.

Outfielder Dominic Canzone (adductor) began a rehab assignment at Triple-A Tacoma on Thursday. Hollander said there is a chance he could be activated during this homestand. Canzone has been out since July 10.