Pomeranz, a deadline acquisition by Boston last season, arrived with a balky elbow that could have killed the deal with San Diego if Red Sox president of baseball operations Dave Dombrowski wanted to kill it.
Not reversing the trade may turn out to be the key to Boston's season.
Pomeranz heads into Friday night's start against the New York Yankees with a 12-4 record, a 3.39 ERA and no losses since June 11, and just one since May 14. He is 6-0 with five no-decisions in his last 11 starts and has won both August outings -- the second against the Yankees in the Bronx last Saturday.
Pomeranz, 9-1 with a 2.70 ERA since May 20, will face rookie Jordan Montgomery in the series opener.
"The one thing that Drew has done, he's kept us in a lot of ballgames because he's found a way to navigate when there's been men on base," Red Sox manager John Farrell said last Saturday.
Montgomery, who pitched a strong game against Sale last Sunday -- one run, two hits in 5 1/3 innings -- comes into this start with his team four games behind Boston in the American League East after sweeping four games against the Mets.
"These are really important games for us because the clock is ticking in a sense," Yankee manager Joe Girardi said after Thursday night's game. "The season is ... I'm not sure how many games we got, 40-something left, but they're really important."
The Red Sox led New York by 5 1/2 games when they left New York, and the lead would have been down to three games if the Red Sox hadn't rallied for three runs in the bottom of the ninth to complete their four-game season sweep (two this week) of the St. Louis Cardinals.
Now, it's rivalry renewed.
"Let's win," Eduardo Nunez, who (along with rookie Rafael Devers) has invigorated the Boston offense since Nunez came over from the San Francisco Giants. "They have a really good team and they have good hitting and good pitching, but we do, too. We'll see how it goes."
The teams play again in the Bronx from Aug. 31-Sept. 3.
Montgomery, a young pitcher whose innings are being watched, is 7-6 with a 3.94 ERA but hasn't won since July 25. In his last two starts, he has worked 10 1/3 innings and allowed just five hits and two runs, walking three and striking out 11. He has a pair of no-decisions against the Red Sox.
Pomeranz has yet to figure out a way to keep Didi Gregorius or Gary Sanchez under control. Gregorius is 8-for-17 (.471) and Sanchez 6-for-13 (.462) with three homers against the lefty. Todd Frazier is 1-for-8.
No Red Sox hitter has more than six at-bats against Montgomery, and that is Wednesday night hero Mookie Betts 1-for-6 (.167). His two-out, two-run double in the ninth Wednesday gave the Red Sox their ninth walkoff win of the season, tied for the major league lead.
New York has been resting the struggling Aroldis Chapman and had to use Dellin Betances to get the last three outs after a Curtis Granderson grand slam made it a 7-5 game in the ninth. He may well be unavailable Friday night.