The San Francisco 49ers got some good news and some bad news on Thursday after the diagnosis finally came in on Nick Bosa's injured hamstring

The good news is that the injury isn't considered serious. The 49ers rookie has been diagnosed with a Grade 1 strain in his hamstring, which is the lowest degree of a hamstring strain. It's the kind of injury that can cause tightness in the back of your thigh, although you're still able to walk normally. 

The bad news for the 49ers is that Bosa's injury is expected to sideline him for several weeks, which means he likely won't be on the field again until the team kicks off training camp in late July. Based on the timeline the 49ers gave for his return, there's almost no way Bosa will be on the field for any of the team's final seven OTA sessions, which are being held between May 23 and June 6. It's also unlikely that Bosa will be able to participate in the team's mandatory minicamp, which is runs from June 11-13. 

Bosa was injured on Tuesday during just his second OTA session with the team. Although a mild hamstring strain isn't a serious injury, you can bet the 49ers will be keeping a close eye on Bosa, who they selected with the No. 2 overall pick in April's NFL Draft. If Bosa had one red flag going into the draft, it was his inability to stay healthy. 

Bosa's injury history dates back to his time in high school when he tore his ACL. Once he got to college, Bosa was able to stay relatively healthy during his first two years at Ohio State, but then the injury bug bit again in 2018. During his final season in Columbus, Bosa only played in three games due to a groin/core muscle injury that he suffered in September. Although Bosa underwent surgery on his core muscle injury in September, he never returned to the Buckeyes because he thought it would make more sense to start preparing for the NFL Draft. 

Before this week, Bosa hadn't participated in a football practice since September, and it's definitely not an encouraging sign for the 49ers that he injured himself in just his second practice with the team.