GAINESVILLE, Fla. — With the season opener less than two weeks away and tailback Matt Jones still on the mend, the Florida Gators are left to rely on an unproven stable of running backs that includes a walk-on and a converted defensive back.

Jones’ absence also leaves quarterback Jeff Driskel as the Gators most-accomplished runner, a dubious situation for a team without an experienced back-up quarterback.

Gators coach Will Muschamp said Jones underwent blood tests on Monday to gauge his level of recovery from a viral infection that has sidelined him for the team’s 20 preseason practices.

The 6-foot-2 Jones has been jogging again and is back to 223 pounds, getting closer to his 226-pound playing weight. He lost as many as 10 pounds due to the virus.

Still, the Gators do not expect Jones to be ready when Toledo visits the Swamp on Aug. 31.

“We’ve planned that way the whole time,” Muschamp said.

Jones’ ailment has forced coaches to adjust their plans.

Jones, a sophomore from Tampa, was slated to step in for 1,000-yard rusher Mike Gillislee and handle a heavy workload in a Gators’ offense reliant on a strong run game.

Asked when Jones might return to the field, Muschamp had no idea.

“I can’t even guess,” he said. “I don’t know. All I know is he is progressing very well.”

As it stands now, Driskel might be the team’s top running threat. The junior from Oviedo rushed for 716 yards and on 82 carries last season, not including sacks.

But coaches do not want to expose Driskel to injury, given no Gators’ back-up has thrown a pass during a college game.

“We’ve talked about some of the design run game and limiting those hits (on Driskel,)” Muschamp said last Friday.

While Jones is sidelined, the running back options are unknown commodities.

Muschamp the team’s top three tailbacks are junior Mack Brown, sophomore walk-on Mark Herndon and sophomore Valdez Showers, who moved from safety during camp.

The 5-foot-11, 215-pound Brown has 167 career rushing yards on 40 carries during three seasons — he earned a redshirt after he appeared in two games as a freshman. Jones, on the other hand, rushed for 275 yards and three scores in 2012 as a freshman, including 162 yards and two touchdowns on 19 carries during the final three games.

Herndon, a 5-foot-9, 194-pound Ocala native, has not carried the ball at Florida. He appeared in six games on special teams last season.

Showers lined up at safety last season but has potential to help. The 6-foot, 190-pound Showers was the 2010 Gatorade Player of the Year in Michigan after he ran for 2,024 yards and 29 touchdowns at Madison Heights (Mich.) High School.

“He’s got great top-end speed,” Muschamp said of Showers. “He’s got really good ball skills. He can do a lot of different things for us as far as lining up at receiver, lining up in the backfield. A tough guy to account for a defensive coordinator.”

Muschamp said freshmen Kelvin Taylor and Adam Lane, who combined for more than 4,000 yards and 53 touchdowns as high school seniors, need to develop as complete backs and fumble less often before either will play.

“You’ve got to take care of the football,” Muschamp said. “That’s the No. 1 thing. They’re very talented runners. So much more goes into it other than just running the football.”