He depended on strong control of his pitches, a good curveball and change-of-pace, and a studious approach to opposing batters.

During the 1879 season with the Shamrocks, his pitching would be credited to their 23–14 record, during which he was supported by the likes of later MLB players Roger Connor, Larry Corcoran, Jerry Dorgan, Peter Gillespie, and Fergy Malone.

[6] Welch's totals dipped during the following two seasons, when Keefe, who also went on to win more than 300 games, began getting a greater share of the starts.

[7] The duo would only enjoy moderate success over the course of three seasons with the Trojans, a team that never finished higher than fourth in the National League during its four-season run.

[3][8] After the Trojans disbanded after the 1882 season, the New York Gothams replaced them, taking many of the Troy players, including Welch.

Welch holds the record for most consecutive batters struck out to begin a game, with nine, set on August 28, 1884.

Baseball historian Harry Simmons helped Welch to receive official recognition of the feat in the 1940s.

In the National League, Germán Márquez of the Colorado Rockies on September 26, 2018, Jacob deGrom of the New York Mets in 2014, and Jim Deshaies of the Houston Astros in 1986 struck out the first eight batters they faced.

[15] Some credit Welch with becoming the first pinch hitter in major league history when he batted for Hank O'Day and struck out on September 10, 1889.

[16] Before the Players' League began its season in 1890, Welch realized that he was coming to the end of his playing career.

He met with sharp criticism from Jim O'Rourke and other Brotherhood members, but the Players' League lasted only one season.

[20] He had unique hitting skills for a pitcher, finishing his career with a .224 batting average, 93 doubles, 16 triples and 12 home runs.

[3] Author David Fleitz writes that Welch did not swear, smoke or drink hard liquor.

Welch liked beer enough that he would write poems about it, reciting them for sportswriters or for fans on the carriage ride to the ballpark on game days.

Giants bat boy Fred Engle speculated that this was because Welch had seen too many ballplayers fall prey to alcoholism.

[24] In 1912, he returned to New York, serving as an usher at the Polo Grounds and captivating fans with tales of his playing days.

[25] In July 1941, Welch had been staying with his grandson in Nashua when he had to be taken to a Concord hospital with complications of gangrene of the foot.

He died there on July 30 at the age of 82 and was interred in Section 4, Range 17, Plot 2, Grave 6 of the Calvary Cemetery in Woodside, Queens, New York, under his birth name of Walsh.