Steelers sign left tackle Alejandro Villanueva to extension

— -- LATROBE, Pa. -- There will be no holdout for left tackle Alejandro Villanueva, who has signed a four-year extension with the Pittsburgh Steelers, the team announced Thursday.

The Steelers didn't disclose financial terms. ESPN's Jeremy Fowler, who first reported the agreement, confirmed an NFL Network report that the deal is worth $24 million.?

Villanueva, 28, wasn't under contract because he hadn't signed his exclusive rights tender of $615,000.

Villanueva was seen arriving at training camp around 3 p.m. ET but was not available to the media.

The two-year starter made significant strides in the second half of 2016 and is a key component to one of the league's best offensive lines.

All five starters -- including Ramon Foster, David DeCastro, Marcus Gilbert and Maurkice Pouncey - are under long-term contracts. The Steelers' line allowed 21 sacks in 21016, second-fewest in the NFL.

"It's rare, especially in this league -- guys all under second contracts doesn't really happen," DeCastro said. "We have to make it show."

Villanueva, an Army graduate, was an undrafted free agent with the Philadelphia Eagles in 2014 before bouncing around the league and eventually landing on the Steelers' practice squad.

He took over the left tackle job when Kelvin Beachum went down with injury in 2015.

"He made some huge improvements last year and he has a lot of room to grow," DeCastro said.