Sen. Chuck Grassley (R-Iowa) has tested positive for coronavirus, he tweeted Tuesday.

Why it matters: Grassley is the second oldest member of the Senate at 87 years old, meaning he is at high risk for a severe infection, according to the CDC. The Iowa senator is the third in the line of succession to the presidency as president pro tempore of the Senate.

What he's saying: Grassley wrote that he is "feeling good" and will continue to quarantine. He did not specify how he was exposed.

• "I’ve tested positive for coronavirus. I’ll b following my doctors’ orders/CDC guidelines & continue to quarantine. I’m feeling good + will keep up on my work for the ppl of Iowa from home. I appreciate everyone’s well wishes + prayers &look fwd to resuming my normal schedule soon"