Steve Henderson was acquired by the Mets from the Cincinnati Reds on June 15, 1977 in the incomprehensible deal that would send Tom Seaver packing. Incidentally, the Mets would make another trade that day, shipping Dave Kingman to the Padres for utilityman Bobby Valentine, who would become the team's manager twenty years later. Before he ever donned a Mets' uniform Henderson was already known as "one of those bums we got for Tom Terrific". Henderson was the Reds' top prospect at the time of the trade, and he made his big league debut the following day at Shea against the Astros, scoring the tying run in the bottom of the seventh after pinch-running for Ed Kranepool. He would strike out in his first official at bat the next inning, but the debut and the run scored got him his first big league sound byte:
"I was very excited at the opportunity to help. I'm glad to be here, I was kind of nervous early this evening, but once the manager (Joe Torre) put me in the game, I felt okay."A week later, on June 23, Henderson came in as a defensive replacement for Kranepool in the top of the 11th inning of a game against the Braves and would hit a walk-off, three-run homerun in the bottom half of the inning. Henderson would go on to hit seven homeruns in his first forty games and twelve in all that season.-- The Washington Post (6/18/77)
Year Age PA XBH BB AVG/OBP/SLG EQA WARP3 VORP -------------------------------------------------------- 1977 24 398 34 43 297/372/480 .303 4.6 25.1 1978 25 654 49 60 266/333/399 .275 4.9 13.0 1979 26 393 29 38 306/380/440 .299 4.5 21.1 1980 27 584 33 62 290/368/402 .288 5.6 16.1

In his second season with the Mets -- his first full season -- Henderson regressed quite a bit, experiencing the proverbial sophomore slump. He lost 31 points of batting average, 49 points of on-base percentage and a whopping 81 points of slugging percentage. His walk rate fell from 10.8% to 9.2%. In his rookie year, Henderson had a BABIP of .355, well above the league average of .290. In 1978 that BABIP fell to .312 compared to the league rate of .283. It's possible that Henderson wasn't hitting the ball as hard in 1978 (fewer line drives) or that the league "caught up to him" so to speak, although it's just as likely that he was much luckier in 1977 that an unusual number of balls fell in for hits and a few extra flyballs fell out of the park instead of into an outfielder's mitt.
Henderson bounced back in 1979 to post AVG and OBP marks more in line with his 1977 marks, and his SLG rebounded too, largely due to the increased batting average. His BABIP shot back up to .355 (the league's was .289). Henderson's resurgence was derailed on July 31 when he sprained his left ankle running from second to third in an eventual 8-5 loss to the Pirates. He would appear as a pinch hitter in the second game of a September 25th double-header in which he singled in the winning run in the top of the tenth inning, but would otherwise miss the remainder of the season.
Henderson recovered from the ankle injury to have another solid year with the bat. He didn't flash much in the way of power, but his good batting average and solid walk rate gave him plenty of value to the team. He was traded to the Cubs prior to the 1981 season for former Met Dave Kingman, but would go on to have a number of nice years with Chicago, Seattle and Oakland before retiring in 1988 at the age of 35 as a member of the Houston Astros.
In his four seasons with the Mets, Steve Henderson posted OPS+ marks of 132, 108, 128 and 118. He wasn't Tom Seaver, but he was a nice player during his time in Queens. The Mets were 260-388 during Henderson's time with the team, but little of that was his fault. Some people may remember him for the wrong reasons, others remember him for a single feat of magic, but Hendu should probably be remembered as one of the better players during a period of time when there was little reason to actually go out and see the Mets.
Sources
Steve Henderson at Baseball-Reference.com
Steve Henderson at Baseball Prospectus