BOSTONDaniel Nava is back in the leadoff spot for the Red Sox tonight against the Tigers for the third straight game.And why not?He has hit in the first spot the last two games, and four times overall in his career. The Sox have won all four games. The last time the Sox won as many of a players first games in the lead-off spot was Steve Lyons first six starts leading off from May 27 through June 9, 1985.Nava had the big hit in the Sox 6-3 win over the Tigers Tuesday night, a two-out, bases-loaded double in the third off Justin Verlander to score all three runners.Thats what you try to teach a player, manager Bobby Valentine said. When the moment is intense, to slow it down. You keep hearing that, that you want to breath and not have things spin too quickly. It seemed like he was all of his at-bats. That at-bat didnt look any different than any of his other at-bats, which is pretty damned phenomenal I think.In 19 games this season, Nava has a .429 on-base percentage. He has reached base safely in 17 of those games.Hes had a pretty good on-base percentage all his life, Valentine said. So he has an ability to see the ball, to not get out of himself.Nava did not even receive an invitation to spring training after spending all of 2011 in the minor leagues despite making his major league debut and playing 60 games the previous season. Valentine has said the switch-hitting outfielder was not even on his radar this spring.Since being called up on May 10, he has started each game in left field.Daniel, his defense has been so good, Valentine said. Hes playing the wall so well. His throws are so accurate. His jumps are so precise. He wouldnt even have to be hitting if you wanted to put him out there because at the beginning of the season that wasnt the case in left field, as some of us might recall. He filled a big hole.Valentine pointed to Nava, along with shortstop Mike Aviles and catcher Jarrod Saltalamacchia, as providing some much needed, and perhaps unexpected stability to the team.Mike Aviles and Salty and Daniel could have created a real different situation if they werent playing as well as theyre playing, Valentine said. We had stability with Dustin Pedroia and David Ortiz and Adrian Gonzalez. But if there wasnt stability at those starts, this would be more challenging than it is. Theyve been great.