ST. LOUIS -- Mets manager Mickey Callaway didn’t even get the chance to fully relax on Saturday night before first baseman Pete Alonso was lobbying to be in Sunday’s lineup. It appears Callaway made the right call.

In his first at-bat, Alonso hit a 444-foot homer to straightaway center off Cardinals right-hander Dakota Hudson to give the Mets a one-run lead. The long blast was also Alonso's first homer off a starter this season.

The ball jumped off Alonso's bat at 114.5 mph, according to Statcast, making it the Mets' fifth-highest exit velocity on a homer since Statcast began tracking in 2015. Alonso, who also had New York's hardest-hit homer at 118.2 mph on April 11, is responsible for two of New York's five hardest-hit homers.

“I was on the way to eat [dinner] with my parents and he’s calling and texting me,” Callaway said on Sunday morning before the Mets' 6-4 loss to the Cardinals.

Alonso was hit on the right hand by a pitch that was ruled a foul ball in the eighth inning of Saturday’s 10-2 loss to the Cardinals. He exited the game in a double switch in the bottom of the inning, but X-rays taken of the hand after the game were negative and he was deemed ready to go for Sunday.

Part of that drive to play was apparently based on Alonso’s familiarity with Sunday’s opposing starter, Hudson. The two both played college baseball in the Southeastern Conference, with Alonso playing at the University of Florida and Hudson at Mississippi State.

“I guess he faced [Hudson] in college,” Callaway said. “He called me last night like, ‘Hey, you better put me in the lineup against this guy.’”

Callaway laughed about Alonso’s vigor and commitment.

“I don’t know what he was saying," the Mets' skipper said. "He was going nuts. He just said he didn’t like him very much. Something like that.”

For his part, Alonso was cagey.

“I played against him in college," Alonso said. "I know him well, and I want to hit against him. Simple as that."

Frazier progressing toward return

Corner infielder Todd Frazier has yet to make his 2019 season debut, but he continued to progress in that direction with a successful rehab appearance for Triple-A Syracuse on Saturday.

Frazier, placed on the 10-day injured list on March 28 with a left oblique strain, went 2-for-3 with a double, an RBI and a run scored in his first appearance for the Syracuse Mets. Callaway said that Frazier is “getting closer” to a return to the Majors.

“He did really well,” Callaway said. “I talked to the Triple-A manager [Tony DeFrancesco] this morning. Some good at-bats.”

Frazier will play for Syracuse again on Sunday. After that, Callaway said the next step will be “evaluating the situation.”

Zamora recalled, Flexen optioned

As Callaway revealed following Saturday’s game, the Mets recalled left-hander Daniel Zamora from Triple-A Syracuse on Sunday morning. Zamora joins the Mets' bullpen after allowing one earned run in five innings for Syracuse this season.

Chris Flexen, who started Saturday’s game as a replacement for the injured Jacob deGrom, was optioned back to Syracuse to open a spot on the active roster. Flexen took the loss on Saturday while pitching 4 1/3 innings, allowing six runs (five earned) on seven hits with four walks and no strikeouts.

UMPS CARE auction underway

The 11th annual UMPS CARE Charities Online Auction is underway online. It runs until 10 p.m. ET on April 29, and offers a wide variety of baseball experiences and memorabilia.

Mets fans can bid on a "GM for the Day Experience" with Triple-A Syracuse, which also comes with tickets for four and a parking pass. There are also signed baseballs available from Michael Conforto and deGrom, as well as a Mets jersey signed by multiple members of the organization.

The auction benefits children battling illnesses, foster youth, military families and college students who were adopted later in life.