Ryan Lavarnway hit his first two major league home runs on Tuesday. (AP)

BALTIMORE — It’s not entirely accurate to say that, entering the year, it would have been impossible to imagine Ryan Lavarnway as the starting catcher on the second-to-last day of the season for the Red Sox.

Even though he was opening the year in Double-A, there was the possibility that the Sox would have wrapped up a playoff spot by the season’s final days, giving them an opportunity to rest their regulars and give a promising prospect a start. Alternately, if the Sox had been knocked out of the race, it wouldn’t have been shocking to see a call-up getting a look.

But in the heat of a pennant race? That scenario seemed nearly impossible to imagine.

But the impossible came to dramatic fruition on Tuesday night, when Lavarnway added another chapter to what has been a huge season for the Sox catching prospect. Jason Varitek was injured on Sunday and unavailable. Jarrod Saltalamacchia was injured on Monday and, while theoretically available, the Sox decided to go with Lavarnway, a rookie who was both healthier and who was not party to the monstrous month-long slump that had afflicted both of the team’s regular backstops.

Lavarnway blasted a pair of homers, becoming the youngest Sox player in 14 years to go deep twice in a game, as the Sox claimed an 8-7 win over the Orioles. With the victory, the Sox remained tied in the wild card race with the Rays, who beat the Yankees by a 5-3 count in Tampa Bay.

Behind the plate, Lavarnway threw out Adam Jones on an attempted steal of third. But, perhaps more importantly, he delivered some much-needed thump to a position where the Red Sox had gotten none.

Sox catchers had a combined .137 average, .180 OBP, .316 slugging mark and .486 OPS. And so, for the Sox, it was a welcome and novel sight when Lavarnway destroyed a full-count fastball by Orioles left-hander Zach Britton, driving it over the left-field fence for a three-run homer that gave the Sox a 5-1 lead in the fourth. He later clubbed a solo homer to left in the top of the eighth, giving the Sox a measure of breathing room that ultimately proved vital.

Now, the Sox will turn to Jon Lester — pitching on three days’ rest for the second time in his career — on Wednesday. With a win, the Sox would be assured that their season will continue — whether in a one-game playoff in Tampa Bay on Thursday or in the AL Division Series on Friday. With a loss, the Sox could find their season at an end.

That said, thanks to an improbable succession of events with their catchers, the Sox still do have their fate in their own hands. For now, there is little more than they can ask for.

WHAT WENT RIGHT FOR THE RED SOX

– Lavarnway became the first Red Sox to hit a homer in his first career start as a catcher since Danny Sheafer homered in his major league debut in April 1987. With his two launches, the catcher now has 34 total home runs this year between his two minor league stops and the majors, tops in the organization.

At 24 years, 51 days, Lavarnway became the youngest Red Sox player with multiple homers in a game since Nomar Garciaparra accomplished the feat at precisely the same age on Sept. 12, 1997.

– Once again, Jacoby Ellsbury sparked the Sox in his increasingly remarkable 2011 season. With the Sox down, 1-0, in the top of the third, Ellsbury blasted a two-run homer to right-center to give the Sox a lead they would never relinquish. It was Ellsbury’s 32nd homer of the year and eighth home run of the month — one shy of his career high for home runs in a season entering 2011. The homer off of Orioles starter Britton was also the sixth of the year by Ellsbury against a southpaw.

Ellsbury has now hit in 12 straight games, making him one of five Red Sox ever to have five hitting streaks of at least 10 games in the same season, joining Hall of Famers Tris Speaker, Jimmie Foxx and Wade Boggs as well as former franchise icon Nomar Garciaparra.

– Marco Scutaro continued his torrid season-ending stretch. The shortstop blasted a two-run homer, his seventh of the year, and he’s now hitting .382 with a 1.009 OPS in September. That strong season-ending performance has Scutaro sitting on a .297 average (best of his career) and .787 OPS (second-best of his career) with one or two games remaining.

– Alfredo Aceves once again demonstrated his exceptional value as a long reliever, replacing Erik Bedard in the fourth inning and tossing 3 1/3 innings while allowing just one run on three hits. Aceves earned his ninth relief win of the year, most by a Sox since Bob Stanley had that many wins out of the bullpen in 1984.

WHAT WENT WRONG FOR THE RED SOX

– Erik Bedard had six strikeouts, tied for his most as a member of the Red Sox, but he once again proved inefficient, resulting in an extremely short, bullpen-taxing outing. Bedard threw 84 pitches (48 strikes) and was lifted after just 3 2/3 innings. In his last two outings, Bedard has now pitched a total of six innings, resulting in his bullpen having to absorb 12 innings in those contests.

– Daniel Bard delivered a shaky inning out of the bullpen. Handed an 8-4 lead in the eighth, he allowed three hits — including a triple by Nolan Reimold — and two runs. Bard now has an 11.70 ERA in 10 September innings.

– Inserted into the cleanup spot with a left-hander starting, Jed Lowrie went 0-for-4 with two strikeouts.