Seattle Mariners Henderson was selected by the
Seattle Mariners in the first round of the
1977 Major League Baseball draft. His first MLB hit came several games into the season—a home run against Oakland pitcher
Steve McCatty, after Henderson had been hitless in his first nine major league plate appearances. He struggled at the plate throughout the season; at the end of April, he was batting .135, which improved only slightly to .172 at the end of May. After then going 1-for-10 at the start of June, he was sent back down to Spokane in Class AAA. Henderson spent much of the summer with Spokane, appearing in 80 games while batting .279 with 12 home runs and 50 RBIs. In early September, he was recalled, with his first appearance back with the Mariners coming on September 3, in a 20-inning game against the Red Sox—one of the longest MLB games ever played. From when he was recalled until the end of the season, he appeared mostly as a late-innings defensive replacement, finishing his first MLB year with a .167 average in 59 games played, with 6 home runs at 13 RBIs. During the season, Henderson's playing time increased significantly, as he appeared in 104 games, with 85 complete games played (all in center field). He batted .253, with 14 home runs and 48 RBIs. In , his batting average improved to .269 with 17 home runs and 55 RBIs, while appearing in 137 games, with 124 of them being complete games in the outfield (78 in center field and 46 in right field). Henderson spent some of the season on the
disabled list because of a hamstring injury. Henderson struggled at the plate early in the season, batting below .200 on May 25. By June 19, he had improved to .263, and he was batting .276 on August 17. Overall, Henderson played with Seattle for parts of six seasons, appearing in a total of 654 games, while batting .257 with 79 home runs and 271 RBIs.
Boston Red Sox On August 19, 1986, the Red Sox, atop the
American League (AL) East, traded for Henderson and shortstop
Spike Owen, sending
Rey Quiñones,
Mike Brown,
Mike Trujillo, and a
player to be named later to Seattle. Henderson was acquired as a backup for Boston center fielder
Tony Armas. Henderson joined the
1986 Red Sox on August 19, and appeared in 36 games over the remainder of the regular season, with just 7 complete games (all in center field). Most of his appearances were as a late-game defensive replacement in center field, or as a pinch hitter – he had only 51 at bats, collecting 10 hits (.196 average) with one home run and three RBIs. The Red Sox finished the season on top of the AL East – games ahead of the
New York Yankees – and faced the winners of the
AL West, the
California Angels, in the
AL Championship Series (ALCS).
1986 ALCS home run Henderson is best remembered for the two-out, two-strike home run he hit in the top of the ninth inning in Game 5 of the 1986 ALCS. At the time, the Angels were playing at home and were ahead in the series 3 games to 1 over the Red Sox. Henderson had appeared in Game 2 and Game 4 as a late-innings defensive replacement for
Tony Armas, and was hitless in one at bat. In Game 5, Armas sprained his ankle in the second inning, and was replaced by Henderson, who entered the game to play center field in the bottom of the fifth inning. With the Red Sox leading 2–1 in the sixth inning, the Angels had a man on second with two out, when
Bobby Grich hit a deep fly ball Henderson attempted to catch on the
warning track – the ball deflected off his glove and went over the wall, giving Grich a two-run home run. The Angels now had a 3–2 lead, with Henderson the likely scapegoat should the Red Sox lose the game. Henderson batted in the seventh inning and struck out, while the Angels added two more runs in the bottom of the seventh. The Angels had a 5–2 lead going into the ninth inning and were three outs away from their first-ever trip to the
World Series, but the Red Sox closed the gap to 5–4 on a two-run home run by
Don Baylor. When Henderson batted against
reliever Donnie Moore, there were two outs and catcher
Rich Gedman was on first after being hit by a pitch. After falling behind in the
count 1–2 – the Angels now one strike away from advancing – Henderson took a ball to even the count at 2–2, and fouled off the next two pitches. Then, on Moore's seventh pitch of the at bat, Henderson hit a drive to left that cleared the outfield wall, stunning the Angels and all of
Anaheim Stadium. Henderson's blast prompted television broadcast announcer
Al Michaels to state, "You’re looking at one for the ages here.” The Angels tied the game 6–6 in the bottom of the ninth, and the game went into
extra innings. In the top of the 11th, the Red Sox loaded the bases with no outs, and Henderson hit a
sacrifice fly Baylor scored on, which put the Red Sox ahead 7–6 and proved to be the margin of victory. Still down 3 games to 2 in the series, the Red Sox returned home to
Fenway Park for the final two games, where they defeated the Angels 10–4 and 8–1 to capture the
AL pennant. Henderson played center field for both of those games – collecting a walk and a run in each game, but going hitless – as Armas' injury kept him from playing. For the ALCS, Henderson finished 1-for-9 at the plate, with his only hit being the season-saving home run in Game 5.
1986 World Series Henderson was the Red Sox' centerfielder throughout the
1986 World Series, as Tony Armas was sidelined by the injury he had sustained in the ALCS; Armas made only a single appearance, as a pinch hitter. Henderson hit .400 (10-for-25) in a losing cause, as the Red Sox were defeated by the
New York Mets in seven games. Henderson hit two home runs – the first during the Red Sox' 9–3 win in Game 2, and the second came in the 10th inning of historic Game 6, giving the Red Sox a 4–3 lead in a game they would go on to lose 6–5.
1987 season Henderson was Boston's starting center fielder for the first month of the season. During April he hit .239 with 3 home runs, six RBIs, and 18 strikeouts. On April 30, the Red Sox called up rookie
Ellis Burks from the minors to be the regular center fielder. Henderson's playing time decrease as he primarily played corner outfield positions, along with pinch hitting. At the end of May, he was hitting .240, then he struggled during June, dropping to a .206 average. After having only six at bats in July, he received more playing time in August and raised his season totals to a .234 average with 8 home runs and 25 RBIs. Over parts of two seasons with Boston, Henderson played in 111 regular season games, batting .226 with nine home runs and 28 RBIs.
San Francisco Giants On September 1, 1987 the Red Sox traded Henderson to the
San Francisco Giants for a
player to be named later (ultimately,
Randy Kutcher). Henderson spent the final month of the season with San Francisco, where he appeared in 15 games, batting for a .238 average. While the Giants won the
National League (NL) West and played in the
NL Championship Series, Henderson was acquired hours past the
postseason roster deadline, thus was not eligible to play for the Giants in the playoffs. After the season, Henderson elected
free agency.
Oakland Athletics 1988 season Henderson signed as a free agent with Oakland before the season. He was the Athletics' starting center fielder on Opening Day, and appeared in 146 games, including 127 complete games in center field. His performance proved to be one of the season's biggest surprises as he set career highs in batting average (.304), runs (100), hits (154), doubles (38), RBIs (94), and
slugging percentage (.525). He also hit 24 home runs, and the Athletics were 23–1 when he homered. He started the All-Star Game for the AL in right field, and was 0-for-2 at the plate before being pinch hit for by
Rubén Sierra in the sixth inning. In August, Henderson hit three home runs in one game, in a losing effort against Minnesota, with all three coming in consecutive at bats off starting pitcher
David West. Henderson's average dipped in the second half of the season and he finished the year at .276 with 85 RBIs and a career-high 25 home runs. The Athletics finished with an 84–78 record in fourth place in the AL West. Henderson had problems with a badly strained right hamstring throughout the season, which limited him to just 20 games and caused him to miss 104 consecutive games between May 5 and the start of September. He hit just 9-for-63 (.143) for the season with 2 RBIs. While Oakland won the AL West (then lost to Toronto in six games in the
ALCS), Henderson was left off the postseason roster due to his injury. For the first month of the season Henderson was the Royals' regular right fielder, however he only hit 9-for-47 (.191) with 2 home runs and 8 RBIs. Over the coming months, he appeared more as DH and was not an everyday player. Through late July, he was hitting .247 with 5 home runs at 31 RBIs, having appeared in only 56 of the team's 103 games. Shortly after his 36th birthday, Henderson retired on July 29, which was his last MLB appearance – against the Twins, he played the final two innings of the game as a defensive replacement in left field. During his 14 MLB seasons, Henderson appeared in 1,538 games, batting .258 with 197 home runs and 708 RBIs. Defensively, he played 1,388 games in the outfield (1,157 in center field), with a .984 fielding percentage. ==Personal life==