If New York Mets right fielder Curtis Granderson played hurt throughout the World Series, few could tell by watching. In fact, hardly anyone knew about the injury as Granderson and the Mets kept the secret even when asked about injured players. 

CBS Sports' David Brown reports that Granderson underwent surgery Thursday morning to repair a torn ligament in his left thumb, which the right fielder suffered during the National League Championship Series. According to the report, Granderson injured his thumb in Game 3 against the Chicago Cubs while attempting to steal second base in the first inning. Cubs catcher Miguel Montero threw Granderson out on a very close play. A close-up during the replay shows Granderson jamming his left thumb into the left foot of Cubs second baseman Starlin Castro. 

Granderson appeared to extend the thumb backwards, which led to the torn ligament. However, he continued to play for the remainder of the postseason: two games (including Game 3 of the NLCS) and all five World Series games against the eventual champion Kansas City Royals. 

In his Thursday afternoon report, Brown states that New York media recently asked the Mets about their injuries, but the team did not mention Granderson and his thumb. Brown said that the Mets discussed only one player. Brown writes,

"Granderson and the Mets had kept his thumb injury under wraps, to the point that when New York media asked recently about the team's health as a whole, the club responded by saying that only Juan Lagares was being evaluated for offseason surgery. Lagares +1, please."

Later in his report, Brown added, "But Grandy, doing what what ballplayers do in that situation, rubbed some dirt on it, or whatever, and kept playing."

Granderson hit only .200 (3 for 15) in the four-game sweep of the Cubs in the NLCS and .250 (5 for 20) in the World Series. However, he hit three home runs and drove in five runs against Kansas City, and his four walks in the five-game World Series gave him an on-base average of .360 out of the Mets' lead-off spot. He also scored six times and struck out only twice. A number of his World Series outs were well-struck "at'em" balls. 

Despite his thumb problem, Granderson slugged .700 with 14 total bases in the World Series thanks to his three home runs. 

Granderson may not have had his best offensive season in 2015 with a .259 average and 11 steals, but he hit 26 home runs while driving in 70 runs and scoring 98 -- mainly as a leadoff hitter -- and posted a 3.9 WAR. He was instrumental in the Mets' division-series win over the Los Angeles Dodgers in which he complied a .389 average (7 for 18) and drove in five runs. He also stole three bases and scored three runs against the Cubs. All of this helped lead Granderson to a 2015 postseason line of .283/.375/.520, 3 HR, 12 RBI, 9 SB,  and 10 R -- a fine performance for a 34-year-old outfielder playing with a torn thumb ligament. 

How much better would Curtis Granderson have performed if not for the injury?