Graduated from Faith Christian Academy in Arvada, Colorado. Attended Missouri State University where he set the school's single-season record with 119 strikeouts (second in conference) and ranked third in the Missouri Valley Conference in ERA (2.53) in 2012. Named the Cubs Minor League Pitcher of the Month for August of 2013 after going 3-0 with a 1.02 ERA (2er/17.2ip) in four games (three starts). Ranked as the Cubs organization's ninth-best prospect by Baseball America entering the 2015 season and ranked as the sixth-best prospect entering both 2013 and 2014.
Posted a 3-2 record with a 4.31 ERA (26er, 54.1ip) in 43 games (one start) for triple-A Iowa...converted nine of his 11 save chances...Struck out 74 batters in 54.1 innings, but also walked 27 batters and had a 1.454 WHIP...Made his Major League debut on May 19 vs. Milwaukee (allowed two unearned runs in a 6th inning that was interrupted by a 1:59 rain delay)...marks his only career Major League appearance...Was designated for assignment by the Cubs on Sept. 13 and claimed off waivers by the Giants on Sept. 20.
Pierce was 4-6 with a 6.14 ERA (43 ER/63.0 IP) in 22 games, 11 starts, for Triple-A Iowa as injuries hindered him throughout the season ... walked 43 and struck out 75, good for an average of 10.7 strikeouts per 9.0 innings ... Was struck in his pitching arm in his first start of the season, April 11 vs. New Orleans, after tossing 3.0 scoreless innings ... spent 10 days on the D.L. before he was activated, April 21 at New Orleans, and tossed 5.0 innings of one-run ball ... Suffered a lat strain, May 2 at Nashville, and landed on the D.L. the following day ... activated, June 13 ... Landed back on the shelf when he left his June 19 start at Memphis with a blister ... spent the minimum seven days on the D.L. before returning, June 27 at Oklahoma City ... Transitioned to the bullpen, July 26, and went on to go 3-0 with a 3.22 ERA (8 ER/22.1 IP) in 11 outings ... walked 13, struck out 35 and held the opponent to a .176 batting average and a .503 OPS.
After missing most of the first half of the season with a back strain, Pierce Johnson posted a 6-2 record with a 2.08 ERA (22 ER/95.0 IP) in 16 starts with Double-A Tennessee ... was on Tennessee's seven-day disabled list from April 9-June 11. Struck out 72 hitters while walking 32 in 95.0 innings … allowed just four home runs. Went 6-0 with a 1.61 ERA (11 ER/61.2 IP) including six quality starts in his first 11 starts of the year. Allowed zero or one run in 10 of his first 11 starts of the season. Went 4-0 with a 1.74 ERA (8 ER/41.1 IP) at home compared to a 2-2 mark with a 2.35 ERA (14 ER/53.2 IP) on the road. Limited left-handed hitters to a .157 batting average (20-for-127) while righties batted .262 (56-for-214). Opponents were just 5-for-42 (.119) against him with runners in scoring position and two outs in an inning. Struck out a combined 25 hitters while allowing no runs in the second or third innings in any of his 16 starts.
Pierce made his first appearance at the Double-A level, starting 17 games for the Smokies ... also made two starts with Kane County after returning from the disabled list in June ... Began the season on the disabled list with a right hamstring strain, making his first appearance on April 22 with Double-A Tennessee ... missed nearly a month of action after straining his left calf on May 19, returning on June 22 ... made two appearances with Single-A Kane County upon returning from the second D.L. stint, allowing three earned runs in 11.0 IP (2.45 ERA) ... Spent the rest of his campaign with Double-A Tennessee, where he went 5-4 with a 2.55 ERA (26 ER/91.2 IP) in 18 games (17 starts) ... Went 4-3 with a 1.80 ERA (13 ER/65.0 IP) in 12 starts between July and August ... Righties and lefties sported identical .194 batting averages against him.
Pierce made a career-high 23 appearances, including 21 starts, as he split the season between Single-A Kane County and Single-A Daytona ... Went 11-6 with a 2.74 ERA (36 ER/118.1 IP) between the two clubs ... Went 5-5 with a 3.10 ERA (24 ER/69.2 IP) in 13 starts with Kane County to begin the season ... was promoted after allowing no runs in 7.0 innings against Wisconsin on June 16 ... In 10 games with Daytona, the righty went 6-1 with a 2.22 ERA (12 ER/48.2 IP) ... fanned 50 batters while walking 21 ... Did not allow a single earned run in five of his 10 appearances for the Daytona Cubs ... fanned at least three batters in each outing ... Earned Cubs Pitcher of the Month honors for August after going 3-0 with a 1.02 ERA (2 ER/17.2 IP) in four games (three starts).
Made his professional debut after being selected 43rd overall in the June draft ... started six games between Rookie-League Mesa and Single-A Boise ... Did not allow a run in his two appearances with Mesa, allowing four hits and walking none in 3.0 IP ... Made four starts with Boise, going 2.0 innings in each appearance ... allowed four earned runs in 8.0 innings (4.50 ERA) with 12 strikeouts and three walks.