A tweeted picture of Arian Foster's hamstring could be a tear, according to one doctor, and might keep him off the field for weeks.

The Houston Texans star running back tweaked his hamstring during a preseason win over the San Francisco 49ers and went for a MRI on it Wednesday. After the game, the Texans had a very positive outlook on his injury but there was some uncertainty for whether he'd start Week 1.

After his MRI on Wednesday, Foster tweeted out a picture of the MRI and posted that it was known in the medical world as anti-awesomeness.

Injury analyst Dr. Michael Kaplan reviewed the MRI and told ESPN that it looked like at least a mild to moderate strain, meaning he's torn some of the muscle fibers - a Grade one to two (strain).

With a mild strain, Kaplan said it's going to be a couple weeks at least (before he can play) and that it's very unlikely (Foster is ready for Week 1).

Realizing a media firestorm was developing, Foster later tweeted If I had a significant injury why post it? I'll be fine, it was jus (sic) meant to make fun of the whole situation. Humor is lost nowadays.

Even with Foster's argument it was all a joke, the Houston Texans and millions of fantasy football owners have major reason to be concerned about Foster's injury. Foster had a monster year last year for the Texans -- running for more than 1,600 yards -- and is expected to finally help the Texans become a playoff teams.

In the fantasy football world, Foster is considered to be one of the top players in the game and is consistently taken among the first three picks of any draft. Potentially losing a major player like that for multiple weeks could be disastrous for fantasy football owners.

Texans management has been mum on Foster's MRI, but even if it isn't as bad as Dr. Kaplan made it out to be, it still could be a tenuous situation. Hamstring injuries can hamper a player for whole seasons and really limit potential production. A nagging hamstring injury could certainly bother Foster all year and significantly limit his effectiveness.

For fantasy football owners it's best to show caution in proceeding forward with Foster. There's no need to full-on panic just yet -- at least not until a Texans team doctor officially rules him out -- but it would be wise to pick up a backup Texans running back.

Derrick Ward is listed as the backup on the depth chart, but Ben Tate or Steve Slaton are more likely to get the lion share of the carries if Foster is expected to be out for significant time. The situation could end up proving to be just hype and Foster turns out fine, but it still is worth having a Texans backup for the duration of the season.