ST. PETERSBURG, Fla. — From part-time starter earlier in his career to an important cog on a team trying to get back to the World Series, Texas catcher Mike Napoli is having quite a season.

The offseason acquisition helped the Rangers take a 2-1 lead in their AL division series Monday night, going 2 for 3 with a go-ahead homer, throwing out a runner and even stealing a base in a 4-3 victory over the Tampa Bay Rays.

The defending AL champions will try to wrap up the best-of-five matchup Thursday at Tropicana Field, sending left-hander Matt Harrison to the mound against rookie Jeremy Hellickson.

The Rangers have won four consecutive ALDS road games — all against the Rays. A fifth will put them in the AL championship series for the second straight year.

Napoli, who batted .320 with 30 homers and 75 RBIs in 113 games during the regular season, is one of the reasons they like their chances of reaching the World Series again.

“He’s gotten so many big hits for us this year, you just would shudder to think where we’d be without him,” Rangers CEO and president Nolan Ryan said.

“I feel good at the plate,” added Napoli, who’s done plenty of damage against the Rays since joining Texas after being traded twice within five days in January. “I’m glad I can contribute and help us win.”

Napoli singled and stole a base in the second. He hit a two-run homer off All-Star David Price for a 2-1 lead in the seventh, then threw out B.J. Upton trying to steal second to help a shaky bullpen thwart Tampa Bay’s bid to overcome a three-run hole over the final three innings.

Rays manager Joe Maddon, who’s known Napoli since the 29-year-old was a minor leaguer in the Angels system, proclaimed this to be “the year of the Napoli.”