Retiring Michigan Sen. Gary Peters on Monday endorsed Rep. Haley Stevens as his successor over progressive favorite Abdul El-Sayed in the party's fast-approaching primary.

Peters says Stevens “will be ready on Day One to fight for Michigan” and is among those in a growing effort within the Democratic establishment to help her defeat El-Sayed, according to the Associated Press.

The push is largely over concerns that El-Sayed is too far left to win the General Election. The state primaries are August 4. Democrats are trying to keep the Michigan seat as part of a larger effort to retake control of the Senate.