Jackson was a part time player in '77 and split his time between third and first base, posting a 91 OPS+ in 322 plate appearances. In '78 he again played both positions and hit .297/.337/.421 in 418 trips to the plate.
After the '78 season he was traded with Danny Goodwin to the Twins for Dan Ford. In Minnesota Jackson assumed the starting job at first base and played in a career best 159 games. He recorded career highs in doubles (40) and HR (14) with a slash line of .271/.337/.429. A .227 average with runners in scoring position led to a meager 68 RBI despite 653 plate appearances.
Jackson's strength was found in his defense at first base. Adequate at the hot corner, his range propelled him to the top of the defensive rating for first sackers in the '79 and '80 seasons. He spent the next year and a half as the Twins primary first baseman before a trade sent him to Detroit in the middle of the '81 season.
A free-agent after the '81 campaign Jackson returned to the Angels and enjoyed a productive year in limited playing time. Batting just 159 times, Jackson batted .331/.381/.415 with a career best 119 OPS+. He took on expanded role in '83 as he filled at the corner infield spots for injured Doug DeCinces and Rod Carew. His rate stats all dropped and he batted just .230 in 348 at bats.
Jackson's struggles continued in '84 as he batted .160 and was released in August. He was picked up by the Orioles and played out the season deep on their bench. He spent the entire '85 season at AAA for the Cardinals. With the exception of 18 games for Vancouver in '88, Jackson's playing career was over.
Flipside: As you can see Jackson didn't have much pop for a firstbaseman, topping 8 HR just once in his career.
Oddball: According to baseballreference.com, Jackson's 10.5 chances / 9 innings is the highest career mark among firstbasemen.
History: Jackson played in the playoffs just once in his career and had a pinch-hit single in his only plate appearance in the '82 ALCS. He ended his playing career with a stat line of .259/.314/.385 and 5.8 WAR. "Papa Jack" is better known for his coaching career, especially as the Red Sox batting coach from 2003 to '06.