MILWAUKEE — At long last, Francisco Lindor is back in action. The shortstop returned to the lineup Friday for the series opener against the Milwaukee Brewers, going 2-for-4 with a walk in the leadoff spot. The back issues that have plagued the team’s leader for the last two weeks have not completely gone away, but through rest and treatment, the Mets believe he’ll be able to play through the weekend and into next week. “Good enough,” Lindor said after the Mets lost 8-4 at American Family Field. “Then the pain will come and go. So I’m happy with that.” Lindor led off the game with a walk and dove back to first base without pain. In the bottom of the first, he nearly snared a line drive out of mid air, jumping as normally as he ever did. “I should have caught,” he said. “I should have caught that, but I blame my mom and my dad for making me a little too short.” The pain is mostly when he has to bend over, which is tough for a shortstop. Lindor was charged with an error in the second inning and the runner eventually came around to score. At times, the pain seemed evident. Other times, he looked fine. He didn’t feel as if he was limited at the plate and the rotational movement of swinging a bat didn’t have an affect on his back. The sharp pains that come and go on impact are fine. It’s the dull, nagging pain that limits his mobility that he can’t play through, and probably shouldn’t either. If doesn’t allow him to do much defensively, the Mets would be better off with Luisangel Acuña. But the extra rest over the week bought him a few days. “We’re pretty confident that he is going to be fine,” manager Carlos Mendoza said. “The last day we were in Atlanta, he was in the lineup. We felt comfortable. And then, yeah, two more days, you know?” Lindor last played Sept. 15 against the Philadelphia Phillies, but he managed to play only one inning. The trainers now have to see how he recovers after this game, but he says he can play and the Mets are content to let him. ALVAREZ’S ROUGH NIGHT The running game is once again plaguing the Mets. The Brewers stole six bases Friday night, showing aggression on the basepaths and strong baserunning abilities. This was an issue for the Mets early in the season, with the team being seemingly unable to throw out runners over the first two months of the season. It hasn’t been a strength of Francisco Alvarez to begin with, but the second-year backstop made huge gains in his pop times and throws this season. Friday, he looked like he did earlier in the season. “They’re taking good jumps so it’s tough when the runners get good jumps,” Alvarez said. “I know they’re going they’re going to run a lot. They are aggressive on the bases.” Alvarez also struggled to block breaking pitches in the dirt Friday night. Brice Turang scored after being walked, stealing a base, advancing on a passed ball and then a wild pitch. Mendoza said the Mets will work with Alvarez on adjustments. “I was watching, there were couple of them, and they were tough pitches to block,” Mendoza said. “They moved side-to-side. So, yeah, I wouldn’t put too much into it.” Alvarez hopes to be able to play again Saturday, but if the back spasms continue to limit him, the Mets will have to make a move for another catcher to get through the weekend and Monday’s doubleheader. They don’t currently have another catcher on the 40-man roster, so they would have to make a roster move by designating a player for assignment or moving Kodai Senga to the 60-day injured list. With the Triple-A season over, the Mets have a group of players at their minor league facility in Port St. Lucie working out in case of emergency. PITCHING PUZZLE Left-hander Jose Quintana will start the second game of the series in Milwaukee. They’ll make the decision for Sunday based on lineups, matchups and potentially, what the Braves are doing down in Atlanta this weekend against the Kansas City Royals. You can count out Senga for a start this weekend or next week. The injured right-hander is throwing again after experiencing triceps soreness in his last rehab start, but there is no timeframe for his next step, which is throwing to hitters. “We don’t have that scheduled quite yet,” said president of baseball operations David Stearns. “Whenever he sort of feels ready for it, the next step, the next step would be a live [bullpen].”