MINNEAPOLIS - After Ricky Rubio missed so much time last season due to a severe ankle injury, the Minnesota Timberwolves knew he was susceptible to a few nagging muscle pulls and strains as he started his comeback.

That doesn't make it any easier to get through now that it's happened.

Rubio was listed as questionable for Sunday's game against the Memphis Grizzlies with a mild left hamstring strain that has sidelined him for three games so far. Rubio also missed time in the preseason with a strained quad.

Oklahoma City star Kevin Durant is experiencing a similarly painful comeback from a foot injury that required three surgeries to repair. He also strained his left hamstring last week, and the Thunder said he will miss about a week.

The Timberwolves aren't putting a timetable on Rubio's return, but they have said they will be cautious with him so early in the season. Rubio had an MRI last week that showed no serious issues, and the Timberwolves want to make sure he is fully recovered before putting him back on the court.

Rubio only played 22 games last season because of the badly injured ankle, and the Wolves expected him to face some minor injuries early in the season.

Rubio has been arguably the team's most important player. The Timberwolves are 4-2 with him and 0-3 without him, and he makes a huge impact on both ends of the floor. The Spaniard is averaging 13.0 points and 9.0 assists.

Second-year guard Zach LaVine has been starting at point guard in Rubio's place, but the Wolves sorely miss their veteran starter's ability to organize the offence and provide a strong presence on the defensive end.

The Wolves host the Grizzlies on Sunday, then have a back-to-back in Florida at Miami and Orlando on Tuesday and Wednesday.