DETROIT – The starting pitching has been the best in the league, the bullpen mostly steady and the offense occasionally explosive. Nearly a week into the season, the biggest problem the Twins have encountered is the rulebook.

The Twins can legitimately wonder if they would be undefeated right now if not for a factor that has only been a part of the game for 10 months: The bonus runner on second base in extra innings. They rallied from a two-run deficit Tuesday thanks to home runs by Nelson Cruz and Byron Buxton, but lost 4-3 in the 10th inning when Harold Castro, on base by fiat rather than performance, raced home on Akil Baddoo's two-out, line-drive single to right at Comerica Park.

Speaking of rules that weren't Twins-friendly, Baddoo is only with the Tigers and not one of the Twins' most promising prospects because of something known as Rule 5, which Detroit used to swipe him in December. Baddoo has claimed no malevolence toward his old organization for not protecting him from that rule — but he now owns two singles, a grand slam and five RBI, including a game-winner, in five at-bats against them.

"He's impressive. He's been fun to watch," Twins manager Rocco Baldelli said gamely of the 22-year-old rookie, before adding, "more fun if we weren't playing him."

What is baseball's Rule 5?

The Twins are now 3-2 this season, and both losses came in 10th innings that would obviously have played out differently without the two-base offensive stimulus provided before a pitch was thrown. In Milwaukee, the winning run scored on what might have been a double-play ball without the help.

And Tuesday, Baddoo might never have batted, since Twins reliever Hansel Robles got two quick outs before intentionally walking Robbie Grossman. Of course, both teams get the man-on-second advantage, and just as they did last week, the Twins squandered theirs. This one was particularly painful because Jorge Polanco got to third base with no outs on a Nelson Cruz single. But after a Max Kepler strikeout, Polanco bolted toward the plate on Buxton's chopper to third, and was thrown out.

Making it worse: It was the second time in the game that Polanco had headed home from third base immediately upon the batter making contact, and it was the second time he was thrown out when the ball was grounded straight to an infielder.

BOXSCORE: Detroit 4, Twins 3 (10)

Baldelli said he had no regrets for giving Polanco those instructions.

"If the balls are not hit directly at an the infielders, those are easy runs. We're going to score a lot of runs doing that this year," Baldelli said. "When the balls are put in play and they happen to be directly at infielders, you're kind of in a tough spot, but you're still forcing the other team to make a play."

The Tigers did, spoiling some heroics from a couple of big bats glad to be back in the lineup.

Cruz, who punctuated his first start of the season Monday with two home runs, connected again off Michael Fulmer in the seventh inning, launching a high fastball just over the angled wall in right-center. The opposite-field blast was his 20th career homer in Comerica Park and narrowed Detroit's lead to one run.

Then came Buxton, whose sudden exit from the Twins' lineup in the middle of Sunday's game in Milwaukee was almost as surprising as his dramatic return.

Finally recovered from a virus that afflicted him three innings into the season's third game, Buxton reappeared suddenly in the fifth inning, a defensive replacement for rookie Brent Rooker. When it came his turn to bat in the eighth, the center fielder cracked a 451-foot home run into the left field seats at Comerica Park, a blast with an exit velocity measured at 114.1 mph, his hardest-hit ball ever.

In case you were wondering how his offseason strength program is affecting him.

"He's been a good offensive player, but watching him work on taking this thing to the next level is going to be really interesting," Baldelli said. "Watching him just completely change ballgames single-handedly is just something that never grows old."