Sources: D-backs trying to land ace

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

This year, Towers wants 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.

Diamondbacks executives have been meeting Tuesday behind closed doors at a hotel in Los Angeles, where they are in town for a series with the Dodgers.

They need to counter the deals the Dodgers made for Shane Victorino, which was completed Tuesday morning and the Giants’ reported deal for Hunter Pence, which is close.

While Philadelphia Phillies left-hander Cliff Lee and Seattle Mariners righty Felix Hernandez would be two leading possibilities, it is not clear whether either is the Diamondbacks’ target.

The Mariners, who have consistently and adamantly denied that they will trade Hernandez, inquired about D-backs right fielder Justin Upton earlier this month, according to a source. Those talks, however, failed to progress.

Lee, meanwhile, is clearly available – and one rival executive said early Tuesday that he had received indications that the Phillies and Diamondbacks had discussed a deal involving Lee and Upton.

Those talks, however, are unconfirmed, and, according to a source, Lee can block a trade to the D-backs. His contract with the Phillies allows him to veto trades to 21 teams.

Money also would be an obstacle to a deal.

The Phillies would need to include a ton of cash to make a Lee trade work financially for the D-backs. Lee is owed at least $87.5 million from 2013 to ’15. Upton is owed $38.5 million over the same years.

The Texas Rangers discussed a Lee trade with the Phillies on Monday, but the Phils were unwilling to offer much financial relief, preventing the talks from gaining traction, sources said.

Even if Lee is not the Diamondbacks’ focus, Towers has the pieces to trade for a similar pitcher – specifically, 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.

Upton’s contract, according to sources, enables him to block trades to four teams – the Boston Red Sox, Chicago Cubs, Cleveland Indians and New York Yankees.

The D-backs, possible sellers at one point, have won eight of their past 11 games to move 3½ games back in the NL West and 6½ games back in the race for the second wild card.