It’s becoming a crowded field in the race for the Republican nomination for president in 2016, and one of them is — Ohio Gov. John Kasich — suggests that the party is more than a little worried about Democratic Party frontrunner Hillary Clinton.

Kasich hasn’t officially declared his intentions to run, but he’s already calling his potential opponent a “formidable” candidate who could definitely take his own state, according to an MSNBC report.

Kasich said on CNN’s State of the Union show on Sunday that Clinton certainly has some recent problems that she’ll have to overcome, but anyone who “underestimated” Clinton will be making a very big error.

Kasich at this point is not considered a top candidate for the Republican party. He was formerly a congressman and was managing director at Lehman Brothers before its famous collapse in 2008 that contribution to the Great Recession. However, his position as governor in a key swing state certainly makes him a powerful voice in the Republican Party.

He said if he does run, it would be for president only, and he wouldn’t take a vice-president position.

Kasich has dropped by New Hampshire and South Carolina, early battleground states that will help him make a decision on whether or not he could be competitive in a race where is name is rarely mentioned among the top competitors, most notably former Florida Gov. Jeb Bush, the current presumed frontrunner for the Republicans.

Sens. Ted Cruz of Texas and Marco Rubio of Florida and Rand Paul of Kentucky have all also thrown their hats into the ring and have a solid showing in early polls.

Hillary Clinton formerly served as Secretary of State after losing the 2008 nomination to Barack Obama, and had before that been a senator for New York and the First Lady to President Bill Clinton in the 1990s. She recently officially declared her candidacy for president.