NEW YORK -- After suffering a complete right patellar tendon tear during the World Baseball Classic on March 16, Mets closer Edwin Díaz continues to make progress.

Mets manager Buck Showalter said on Tuesday afternoon that Díaz has stretched out to throwing from 150 feet on flat ground. But the skipper would not say when Díaz will return to the mound, let alone appear in a game. Showalter did say that he is pleased to see Díaz walking without a limp, which hadn’t been the case until recently.

“I don’t think that it’s fair to the trainers, medical people or to our fans, and most importantly to Edwin,” Showalter said about rushing Díaz’s return to the field or projecting too far in advance. “Edwin is meeting every benchmark of a very serious injury. … We’re taking it step by step. When he pitches, we’re going to be sure that we have crossed all the right hurdles to get there. There is still some unknown there. He is doing his part. He has been diligent.”

Last year, Díaz had a season to remember, saving 32 games with a 1.31 ERA and winning the Trevor Hoffman Award as the best reliever in the National League. Showalter declined to use Díaz’s absence this season as an excuse for the team’s struggles in the bullpen. Entering Tuesday’s action, New York’s relievers are 13-21 with a 4.19 ERA. The Mets' 21 saves are tied for 22nd in the Majors.

“Obviously, [Díaz] was the best pitcher in baseball last year," Showalter said. "It makes it harder, but nothing that can’t be overcome. It pushed everybody up.”

While Díaz has been missed, there have also been bright spots in New York's bullpen. Right-hander David Robertson has a 1.96 ERA and leads the team with 12 saves, while left-hander Brooks Raley has a 0.83 ERA in 26 appearances since being activated from the IL on May 14.