The American League Wild Card race is as tight as can be, with five teams fighting for two spots and separated by 3 1/2 games.

Two of those clubs will go head to head Tuesday when the Mariners host the Red Sox in MLB.TV’s Free Game of the Day. Fans can stream the game for free, and it will also air live on MLB Network at 10:10 p.m. ET (blackout and other restrictions apply).

Seattle and Boston began a three-game series at T-Mobile Park on Monday, with the Mariners pulling off a 5-4 win. Here’s a closer look at this matchup.

How they're doing
Red Sox (81-65, 4th in AL East)
Mariners (78-66, 2nd in AL West)

Boston entered the All-Star break in first place in the AL East, but the club has played sub-.500 ball in the second half and is 2-6 in its past eight games, including Monday’s loss to Seattle.

The Mariners, meanwhile, continue to hang around in the postseason race as they look to end a 19-year run without a playoff appearance, MLB's longest active drought. After going 15-13 in August, the Mariners have started off September 7-4, although they lost two series in a row, against the Astros and D-backs, before defeating the Red Sox on Monday.

The matchup on the mound
Red Sox -- Nathan Eovaldi (10-8, 3.57 ERA)
Mariners -- Tyler Anderson (6-9, 4.20 ERA)

Eovaldi has been Boston’s steadiest starting pitcher this season, and he enters Tuesday’s game having recorded a 1.91 ERA and an 11.2 K/9 in his previous six outings. His last time out against the Rays, the veteran right-hander tossed seven scoreless innings with eight strikeouts in a 2-1 Sox win.

Anderson is coming off his shortest start of the year, as he went 4 2/3 innings and allowed four runs against the Astros last Wednesday. However, he has been a solid addition for the Mariners, who acquired him from the Pirates prior to the Trade Deadline. Over eight starts with Seattle, the left-hander has posted a 3.83 ERA in 44 2/3 frames.

The player to watch
After a rough month of August (.663 OPS), Mariners right fielder Mitch Haniger has gotten back on track in September, and he went 4-for-4 with a tiebreaking three-run homer in the bottom of the seventh inning against Boston on Monday. Haniger has gone deep in three straight games and hit safely in nine of his past 10.

Haniger missed most of 2019 and all of '20 due to injuries, but he has produced a career-high 33 homers with 82 RBIs and 99 runs over 139 games this season.

Don’t forget him
No Red Sox player has more homers since the All-Star break than Hunter Renfroe, who has socked 14 second-half dingers.

Renfroe also leads the team in OPS vs. left-handed pitchers (.907) this season, continuing a career-long trend of success against southpaws. Renfroe has a matchup against a left-handed starter on tap Tuesday with Anderson taking the ball for Seattle.

Picture this
Red Sox rookie first baseman Bobby Dalbec struggled over the first four months, but he’s turned it around lately, hitting 10 homers and recording a .325/.404/.807 slash line in his past 26 games.

Dalbec has registered a 24.5% strikeout rate during his hot streak, down from 37.9% over his first 93 games of the season.

Here’s a look at Dalbec’s rolling strikeout rate per 100 plate appearances (every point on the graph represents Dalbec’s K% over his previous 100 PAs).

Number of note
Based on their -56 run differential, the Mariners’ Pythagorean record is 66-78. However, Seattle has defied expectations by playing extremely well in close games.

The Mariners’ 5-4 win over the Red Sox on Monday was their MLB-leading 31st victory in one-run games. No other team has more than 28 wins in one-run games this season. Seattle’s .633 winning percentage in one-run games ranks third in the Majors.