By Alex Horowitz

According to Ken Rosenthal of FOX Sports, free agent starting pitcher Jon Lester has narrowed down his potential destinations to either the San Francisco Giants or Chicago Cubs. A decision is expected to be made no later than Tuesday.

Lester would instantly join the top of the rotation for either team, but he’d especially be a significant upgrade in the Windy City. The Cubs currently lack a true ace, so Lester would need to carry Chicago’s young pitching staff.

In San Francisco, Lester would most likely slide into the #2 spot in the rotation, behind reigning World Series MVP and 2014 Sports Illustrated Sportsman of the Year Madison Bumgarner. It wouldn’t be a far move for him, either, as he played across the bay in Oakland for the second half of last season.

Jon Lester is expected to decide his final destination within the next 48 hours

Between Boston and Oakland in 2014, Lester compiled a 16-11 record with a very formidable 2.46 earned run average. He was the starting pitcher in Oakland’s eventual loss to Kansas City in the AL Wild Card game, and received a no decision despite allowing 6 earned runs in 7.1 innings.

Lester’s contract will be one of the more expensive ones of this free agent class. According to several reports, a contract seems to be in the range of $140 million for 6 years, although those in Lester’s camp are quietly pushing for a deal in the $150 million / 7 year range (via MLB Trade Rumors).

Alex Horowitz is a senior at Briarcliff High School and is an aspiring sports writer. As a lifelong sports fan, he has rooted for the New York Knicks, New York Mets, and Detroit Lions. You can follow him on Twitter @alexhorowitz3