MINNEAPOLIS (AP) – The Minnesota Twins have been treading water through the first month of the season, doing everything they can to keep pace with their AL Central rivals while Joe Mauer recovered from a mysterious back injury.

Despite a tough early schedule and mediocre performances by top starters Scott Baker and Francisco Liriano, the Twins got through the month at 11-11 and just a half-game out of first place. Now Mauer is finally ready to go. He is expected to play Friday night against Kansas. City at the Metrodome, and the Twins hope the return of their All-Star catcher and reigning AL batting champion will be just the boost they need to get on a roll.

“Obviously that guy in the lineup is going to make a huge difference,” starter Nick Blackburn said. “I’m excited to see him out there and I think we’re all looking forward to it.”

It’s been a difficult five months for the pride of St. Paul. He had surgery in December to repair a painful blockage in his kidney, then developed back problems that caused him to miss all of spring training. The injury went through several diagnoses before team doctors settled on inflammation in the sacroiliac joint, which connects the spine to the pelvis.

Mauer started the season on the disabled list, but has shown steady improvement while rehabbing in Florida. In five games with Class A Fort Myers, Mauer hit .400 in 15 at-bats with two doubles, two walks and four RBIs.

Manager Ron Gardenhire said he will insert Mauer in his customary third spot in the batting order, which will allow slugger Justin Morneau to slide into his more natural cleanup role.

“He’s a great player,” Gardenhire said. “When you have that guy calling a game and controlling a running game, and the way he swings the bat in the middle of your lineup, he’s a good player.”

Mauer has won two of the American League’s last three batting titles, but the Twins may miss him even more on defense. Veteran backup Mike Redmond has been hampered by a groin injury and a sore shoulder, so the team has been using youngster Jose Morales, who has a good bat but has struggled defensively.

Twins catchers have thrown out only one baserunner attempting to steal this season. Mauer, the former Florida State quarterback recruit, threw out 36 percent of base stealers last season.

“He stops everything. He eliminates that,” Gardenhire said. “If the pitchers give him a chance, he will throw them out. So there’s a lot of things he brings. It’s not just one area. That’s why he’s an All-Star.”

Mauer played his last rehab game on Tuesday and traveled up to the Twin Cities to meet with doctors on Wednesday. The Twins were off Thursday, giving him a day to rest up and prepare to take over when the Twins open a series against the Royals on Friday.

Rays manager Joe Maddon said Mauer’s return will change the complexion of the Twins.

“One man can really impact an entire organization, not having him there,” Maddon said. “We’re talking about offensively, defensively, just his presence.”

But the Twins are cautioning fans not to view Mauer as a savior. At least not right away.

“You just kind of plug Joe in there and not try to put too much pressure on him,” Morneau said. “He hasn’t had too many at-bats to get ready for the season. We let him get in, get settled. Hopefully we’ll pick him up for a while and then he’ll do what he can do.”

Even without Mauer, the Twins are starting to show signs of improvement. After a disastrous trip to Boston – they were outscored 17-4 in a doubleheader sweep – the Twins took two of three from Cleveland and Tampa Bay to move to .500.

Gardenhire plans to take it easy with Mauer initially, fearing too much work too soon could cause the back injury to flare up again.

“As far as back injuries go, I think everyone in the world knows that those aren’t fun and they can come back up,” Gardenhire said. “We’ll just have to play it by ear.”

AP-ES-04-30-09 1838EDT