Arizona Diamondbacks general manager Kevin Towers likes to refer to the final hours before the non-waiver deadline as “the lightning round.”

On Tuesday, Towers would like to make some thunder.

The Diamondbacks are trying to pull off a blockbuster for a premier starting pitcher, according to major-league sources. The identity of the pitcher is not known.

Towers has the pieces to make such a deal happen – specifically, right fielder Justin Upton and a stable of top pitching prospects.

D-backs officials all but dismissed the possibility of trading Upton last week, but Towers repeatedly has said that he will move any player in the right deal.

By including Upton, who is signed for $9.75 million next season, $14.25 million in 2014 and $14.5 million in ’15, the D-backs would create financial room for an established veteran starter.

The D-backs, winners of eight of their last 11 games, are just 3½ games back in the NL West.

-Ken Rosenthal