from Kevin Allen of USA TODAY,

Here are the top unrestricted free agents expected to be available on July 1:

1. Defenseman Matt Niskanen (Pittsburgh Penguins): The defenseman pool is shallow, and Niskanen, 27, is coming off a breakthrough season. He's a puck mover and has improved his defensive play. With the Philadelphia Flyers' Andrew MacDonald signing for $5 million a season, Niskanen's expectations might start at $5.5 million and move upward. The Penguins want to re-sign him, and he likes it in Pittsburgh. He'll have to decide whether he wants to swing with all of his might or take slightly less to stay with the Penguins.

2. Right wing Ryan Callahan (Tampa Bay Lightning): He wants a lot of money, but he's a tough-minded, gritty forward with offensive spark. He's a leader, always popular in the dressing room. He's first in line when there's a scrum, and his style is very effective in the playoffs.

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