The World Series teams were a testament to the power of starting pitching. Washington’s high-priced trio of Stephen Strasburg, Max Scherzer and Patrick Corbin matched up against Houston’s Gerrit Cole, Justin Verlander and Zack Greinke.

That theme showed how much work the Twins might have to do in the offseason to close a gap.

For the first time, former Cy Young winners (Scherzer, Greinke) squared off in a World Series Game 7. Strasburg was the Series MVP. Cole made a case he’s worth a landmark free agent deal. Corbin showed why he was so sought after as a free agent last offseason. Verlander, though winless in World Series games, is a cinch Hall of Famer, and who would kick him out of their playoff rotation?

The series revealed just how much starting pitching matters in the postseason. And now that the 2019 season is officially over, the hot stove league is approaching quickly and the focus will shift to teams like the Twins, who are coming off a 101-win season but nose-dived out of the playoffs in the first round, partly because their starting rotation (or lack of it) let them down.

The path to spring training 2020 started Thursday, as the five-day window in which teams can negotiate exclusively with their own free agents opened. Players also can start filing for free agency. For the Twins, that means they can consider bringing back righthanded pitchers Jake Odorizzi, Kyle Gibson, Michael Pineda and Sergio Romo; catcher Jason Castro; and second baseman Jonathan Schoop.

With catcher Mitch Garver and second baseman Luis Arraez taking on big roles in the offense, Castro and Schoop aren’t expected back.

But with four of the five spots in the starting rotation undetermined, the next few days should be interesting.

With Jose Berrios the only starter definitely returning next season — he’s eligible for arbitration — Odorizzi should be getting a phone call from the Twins about sticking around a few more years. The 29-year old righthander was 15-7 with a 3.51 ERA as he fixed mechanical issues to have the best season of his career.

Baseball's free agents by position

“I really enjoyed my two years here and I think I’ve been pretty straightforward about that,” Odorizzi said on Oct. 8 after the Twins were eliminated by the Yankees in the AL Division Series. “I try to be as straightforward as possible with just about everything. That’s just the kind of person I am and if I’m back that would be great. I’ve really taken a liking to here. If not I wish nothing but the best for everybody. This is a great group top to bottom.”

Odorizzi had the best season of the pending free agents. Pineda surged during the end second half of the season — until he tested positive for a diuretic and was slapped with a 60-game suspension, of which he still needs to serve 39 games. Gibson was slowed by a the E. coli bacteria during the offseason and ulcerative colitis during the season, and his pitching showed. He went 13-7 but had a 4.84 ERA.

Martin Perez, 10-7 with a 5.12 ERA, has a $7.5 million club option for 2020 that the club has until the end of the five-day window to pick up.

The Twins will pick up Nelson Cruz’s $12 million option, but indicated nothing about Perez, which is telling.

The end of the five-day period also is the deadline for the clubs to make qualifying offers to their own free agents. The qualifying offer this offseason is $17.8 million, which is the average of the top 125 salaries in the game. Players have 15 days to accept the offer or reject it and test free agency. Any team that signs them has to relinquish a draft pick. The Twins could struggle to find common ground with Odorizzi and extend a qualifying offer to see if he accepts it.

At the end of Monday’s five-day window, free agency begins on Tuesday. Teams can officially sign their own free agents back while casting other lines into the free agent ocean.

With the 2019 season wrapped up, work on the 2020 roster is just starting.