What's gotten into Pittsburgh?

There are years when the Pittsburgh Steelers may go an entire offseason without signing four free agents.

This week they decided to sign four players in one day.

So what happened?

In addition to retaining veteran safety Ryan Clark, the Steelers also added safety Will Allen and receivers Antwaan Randle El and Arnaz Battle. Pittsburgh reportedly dished out at least $25 million worth of contracts Monday, although the amount for Randle El’s three-year deal isn’t known.

Retaining Clark was a goal for the Steelers, despite some rough patches in negotiations. He was visiting with the Miami Dolphins Monday, but a four-year deal was reached with Pittsburgh. Clark will return to his natural spot as the starting safety opposite Troy Polamalu.

The other three signings all have a significant theme: Improving special teams.

Pittsburgh's return and coverage teams were an underlying weakness that contributed to last season's 9-7 finish. Allen can be a backup safety and a core player on coverage teams, while both Battle and Randle El have experience returning kicks. Battle can play in kick coverage, as well.

The Steelers recently hired Al Everest to coach special teams this upcoming season. Everest now has some new toys to play with thanks to Pittsburgh's rare, but busy, day in free agency.